After surging to a 13-3 record in 2020, breaking New England's stranglehold on the AFC East title and advancing all the way to the conference championship game, the Buffalo Bills were considered heavy favorites to repeat as division champs in 2021 and make a run at the Super Bowl. The resurgent Patriots have rewritten that script and the Bills have already lost two more games this year than they did in 2020. One thing is as true as it was before the season began, however: The Bills remain one of the most talented and dangerous teams on the Tampa Bay Buccaneers' schedule.

The quickest way to demonstrate that fact is to note that, even after losing 14-10 to the Patriots on Monday night and gaining only 230 yards, the Bills still lead the entire NFL in both point differential (+11.7) and yardage differential (+103.7) per game. Given that the Buccaneers are fourth and second in those two categories, as well, the meeting on Sunday between these two "final four" teams from last year's playoffs is one of the premier games on the entire NFL schedule.

The biggest factor in the Bills' steady climb from six wins in 2018 to 10 in 2019 and then 13 last year was the development of quarterback Josh Allen, the seventh-overall pick in the 2018 draft. Allen had accuracy issues as a rookie, completing just 52.8% of his passes in 11 starts but made improvement in that area (58.8%) in 2019 before his stunning leap to stardom last year. Allen's almost unprecedented jump to a 69.2% completion rate unlocked an otherwise loaded skill set to produce 37 touchdowns against just 10 interceptions, a passer rating of 107.2 and very real consideration for league MVP honors.

Allen's passing numbers have dipped a bit in his fourth season from those 2020 heights but he is still performing quite well and remains the same dual-threat runner he's been since arriving in the league. Last year's trade for former Vikings wide receiver Stefon Diggs also helped Allen make that leap, and Diggs is once again closing in on 1,000 yards in 2021. More on both the quarterback and receiver below.

Buffalo's rushing attack doesn't really have one star workhorse back but it does operate behind a very good offensive line and is still generating 116.7 yards per game and 4.52 yards per carry with the likes of Devin Singletary, Zack Moss and Matt Breida. Obviously, the 35 rushing yards per game provided by Allen helps as well. Tampa Bay's defense has had mixed results against more mobile quarterbacks this season and Head Coach Bruce Arians knows that will be an area of emphasis this week against Allen.

"It's going to be a hell of a challenge," said Arians. "When you've got a dual-threat quarterback like Josh [Allen], it's not easy. They're in empty sets and you're expecting passes and they've got quarterback powers and quarterback counters. He's their leading rusher, just about, and then he can sling it around to all those great receivers he has. So, it is a really big, big challenge defensively for us."

The Bills' defense recently lost one of its best players with the torn ACL suffered by cornerback Tre'Davious White on Thanksgiving but it features a pair of star linebackers in the middle in Matt Milano and Tremaine Edmunds and the front line is loaded with first-round talent. So far, it has all added up to the NFL's top defensive ranking for the Bills, as they are allowing just 272.3 yards per game. Buffalo also ranks second in scoring defense with 16.3 points allowed per contest.

With former Buccaneers Defensive Coordinator Leslie Frazier now in the same roll in Buffalo, the Bills are also first in the league in yards allowed per play (4.60), passing yards allowed per game (165.3) and play (5.35) and first downs allowed per game (16.5).

"They've got a hell of a pass rush and a ton of speed," said Arians "I think Leslie Frazier is one of the best coaches in the league, as is Sean McDermott, so yeah, we're going to have our hands full and we're going to need a lot of fan support."

Indeed, the Buccaneers will have the crowd on their side for the first time in a while after securing consecutive road wins in Indianapolis and Atlanta. However, the Bills have actually been a better team on the road so far this season, winning four of six and most recently drubbing the Saints, 31-6, in the Superdome in Week 12. Buffalo was also able to get out of the very hostile environment of Kansas City's Arrowhead Stadium with a 38-20 win back in Week Five. The Buccaneers are trying to extend their current winning streak to four games and even possibly clinch a division title this weekend but they'll have to do it against a talented Bills team that knows time is running short to retake control of the AFC East race. Here's a closer look at some of the challenges and opportunities the Bucs will face when they finish up their season series with Atlanta on Sunday:

BILLS DIFFERENCE-MAKERS

Like the Washington Football Team, Buffalo fields a defensive line made up entirely of former first-round picks, including rookie end Gregory Rousseau and 2019 ninth-overall pick Ed Oliver. The Bills also have very good depth up front with the likes of Mario Addison, Vernon Butler, Harrison Phillips, Boogie Basham and A.J. Epenesa. While White is clearly the star of the secondary, safety Jordan Poyer might be its most underrated player; he leads the team with five interceptions and also second to Edmunds with 64 tackles. In addition to the aforementioned Allen and Diggs, the Bills' passing game features high-volume slot receiver Cole Beasley (63 catches) and a very productive tight end in Dawson Knox (429 yards, seven touchdowns). By reaching agreement on new three-year deals with tackle Daryl Williams and guard Jon Feliciano in a span of three days this past March, the Bills also kept intact their strong offensive line. In addition to all of those Buffalo standouts, here are four other difference-makers who will challenge the Buccaneers on Sunday:

1. QB Josh Allen. The starting quarterback is the number-one difference maker, good or bad, for nearly every team of course, and thus are often not highlighted in this section. But Allen is a different sort of challenge than most passers, and this is the first time the Buccaneers' defense is going to get an up-close look at him. Allen has a powerful throwing arm and even if his completion percentage and passer rating have dropped a bit from their astronomical heights in 2020, to 65.7% and 97.5, respectively, he's still one of the most productive passers in the NFL with 3,216 yards (seventh in the NFL) and 26 touchdowns (fourth). Allen has been making plays with his legs since he entered the league, with more than 400 rushing yards and eight rushing touchdowns in each of his first three seasons. Last year, Allen threw for 4,544 yards and 37 touchdowns – both franchise single-season records, and also ran for 421 yards and eight scores, becoming the first player in NFL history to have at least 4,000 passing yards, at least 30 touchdown passes and at least eight rushing touchdowns in a single season. This year he has added another 422 rushing yards and three scores and his average of 5.6 yards per carry is up by a yard and a half over last year. He is also the only quarterback in league history with seven-plus rushing touchdowns in three straight seasons, and you're probably screaming the name Cam Newton right now but that note is accurate.

2. LB Matt Milano. This past offseason, Buffalo faced a tough choice with tackle Daryl Williams and linebacker Matt Milano both headed for free agency and the team in a tight salary cap spot. However, the Bills managed to re-sign both of those core players and Milano is making them feel very good about that decision with perhaps his best season yet. An excellent coverage linebacker, Milano plays the WILL 'backer spot for the Bills and has 22 passes defensed and four interceptions over the past four years. Milano wanted to stay in Buffalo and took a below-market deal to do so, and he has responded, according to Defensive Coordinator Leslie Frazier, by playing with a higher level of intensity than ever before. Frazier says Milano is now much more of a vocal leader on the field and that his sense of urgency has infected the rest of the defense. At 6-0 and 225 pounds, Milano is fleet of foot and fluid to the football, and he's a sound tackler at the point of contact. He ranks third on the team with 63 tackles and also has a sack and 14 tackles for loss. That TFL total is more than double that of any other player on Buffalo's defense and it ranks fifth in the league overall and first among non-edge rushers. Mills was originally a safety at Boston College and he wasn't drafted until the fifth round, but he has used his speed, intelligence and hitting ability to develop into one of the most rangy and productive linebackers in the NFL.

3. WR Stefon Diggs. The Bills traded the 22nd-overall pick in the 2020 draft to the Vikings to get Diggs, who wanted out after five seasons in Minnesota. The Vikings used that pick to nab LSU's Justin Jefferson, who has quickly developed into one of the NFL's best receivers. That said, there is absolutely no regret about that deal in Buffalo. All Diggs did in his debut season in upstate New York is set franchise single-season records with 127 catches for 1,535 yards. Both of those totals also led the NFL in 2020 and no player has produced more than Diggs' 198 receptions since the start of last season. Of course, Diggs was an established star before he headed to Buffalo, with consecutive 1,000-yard seasons under his belt for Minnesota in 2018 and 2019, and he gave the Bucs a taste of what he could do in a 2017 meeting with eight catches for 173 yards and two touchdowns. Diggs isn't on quite the same torrid pace in 2021 as he was last year, with his per-game yardage average dropping from 95.9 to 74.8 and his yards-per-target sliding from 9.2 to 8.3, but he still leads the Bills in receptions, yards and touchdowns (tied with Dawson Knox). Diggs has been one of the best deep-ball receivers in the league for years but he's also quick and twitchy and very productive on crossing routes and other plays over the middle of the field. He can make defenders miss and is adept at piling up yards after the catch.

4. LB Tremaine Edmunds. If Milano is the prototypical modern outside linebacker – smaller and faster than those of past decades – than Edmunds is an absolutely huge middle linebacker for today's NFL at 6-5 and 250 pounds. It happens to work because Edmunds is also a ridiculously-gifted athlete who ran a 4.54-second 40-yard dash at the 2018 NFL Combine. With that size and speed, Edmunds could potentially be an edge rusher, and he does have 5.5 sacks in four seasons, but he also has four interceptions and 26 passes defensed. His height is bothersome for opposing quarterbacks trying to make quick throws in the middle of the field. Edmunds had at least 115 tackles in each of his first three seasons in Buffalo and he currently leads the team with 69 stops to go with four tackles for loss, one interception and two passes defensed. He has already been named to two Pro Bowls but is still only 23 years old; he was the first player in league history to have two 100-tackle seasons by the age of 21.

STRENGTHS

Like Tampa Bay, Buffalo has protected its quarterback well in 2021, ranking fourth with a sacks-per-pass-play rate of 4.24%. The Bills rank eighth in passing yards and 13th in rushing yards and keep the sticks moving with the sixth-most first downs per game in the league. Most importantly, Buffalo's offense is hard to stop on third down, converting on 48.4% of those opportunities. The Bills' defense has produced 16 interceptions, third-most in the NFL, and 26 takeaways overall, which is tied for second. And, like the offense, it has dominated on third downs, allowing a 32.0% conversion rate that is third best in the league. Here are some more specific ways in which the Bills have excelled in 2021:

·    One way Buffalo's defense has suppressed their opponents' yardage and point totals is by very rarely giving up the big play. The Bills have allowed only 26 plays that gained 20 or more yards all season, the fewest in the NFL. Twenty of those have been passes (also a league low). Only four of the 21 touchdowns Buffalo has surrendered have been on plays that covered 20 or more yards, tied for the second fewest allowed in the league. Buffalo's total of 119 plays allowed that gained 10 or more yards is also an NFL low.

·    The Buffalo coaches apparently are adept at putting together a game-opening play script, and the players have executed it well. Buffalo has scored 44 points on 12 opening drives this season, with five touchdowns and three field goals. Only Kansas City, with 47 has scored more. The Bills, Chiefs and Vikings are all tied for the highest percentage of opening drives (66.7%) that produce points.

·    Tampa Bay's offense will need to stay ahead of the sticks on Sunday because the Buffalo defense is practically impenetrable on long third downs. Bills opponents have tried to convert 76 third downs when needing seven or more yards and made it on just 12 of them. That 15.8% success rate is the lowest allowed by any NFL defense this year. It's even worse if the yardage needed on third down is 10 or more yards. Buffalo has faced 53 such attempts this year and only allowed three to get past the sticks. That's a 5.7% success rate for Bills opponents, the lowest in the league and the only team mark below 10%.

·    One of the reasons that Buffalo's offense has been so good on third downs this season is that they are frequently able to shorten up the tries by running the ball very well on second down, sometimes with Josh Allen taking care of the issue himself. Buffalo has run the ball on second down 113 times this season and only four of them have lost yardage, the second-lowest total in the league in that situation. Meanwhile, the Bills have gained three to five yards on 33 of those plays and six or more on another 43 to end up with a second-down rushing average of 5.36 yards, second best in the NFL.

WEAKNESSES

Buffalo quarterback Josh Allen has thrown 10 interceptions this season, the same as Tom Brady, but the Buccaneers throw the ball a lot more often than the Bills do. Thus, while the Bucs rank seventh in the NFL in interception rate, the Bills (who also have one pick thrown by Mitchell Trubisky) are 21st in that department. Buffalo's sack rate on defense (5.66%) is still only 24th in the NFL despite the young additions to their defensive front. In addition:

·    In a very strange anomaly that may just be a coincidence, a Bills offense that is among the best in the league at converting third downs has a ton of trouble when it only needs one yard. Buffalo's conversion rate on third-and-one is 52.4%, which is only a bit higher than its overall mark of 42.9% and far below the league average of 69.2% Buffalo has tried to run the ball on third-and-one 13 times and been stone-walled on all but six of them. The league converts third-and-one runs at nearly a three-quarters clip but the Bills are one of only three teams to convert less than half of them. In another strange coincidence, Buffalo's defense is also great on third downs overall but terrible at stopping third-and-ones. Opponents have converted on 88.9 of such tries against them, tied for the second worst mark in the league.

·    The Buccaneers ran well on first down in their Week 12 win at Indianapolis but struggled in that regard the next weekend in Atlanta. This Sunday's game could be a chance to get back on track in that regard, as Buffalo's defense has not stopped the run well on first down. Opponents are averaging 4.72 yards per carry on first down, the fifth-worst average in the NFL, and 28.7 of those carries have gone for six or more yards.

·    Buffalo has been a highly-penalized team this year, ranking in the top 10 for most penalties called against them (100), most accepted (82) and most yards penalized (716). On defense, the Bills have been flagged for defensive holding 15 times, with 12 accepted, both the highest marks in the league, and have also had six roughing-the-passer calls, fifth most in the league. On offense, Buffalo has committed 24 holding calls and 16 false starts to rank 24th and 25th in those categories, respectively.

·    The Bills have the highest average margin of victory in the NFL, having earned their seven wins by an average of 26.14 points per game. However, they have had trouble when the games have come down to the wire. Buffalo has played two games that were decided by three or fewer points and lost both of them, and they've played four games decided by eight points or fewer and lost all of them. Buffalo and Houston (2-10 overall) are the only teams yet to win a game this season decided by one score or fewer.

NEW FACES IN 2021

The Bills worked on their edge rush this offseason after finishing in the middle of the league pack in sacks in 2020, beginning with the first-round pick we will discuss below. Buffalo also used its second-rounder on Wake Forest defensive end Carlos Basham and picked up Efe Obada as a free agent, each of whom has 1.5 sacks this year. The Bills brought in a new backup for quarterback Josh Allen in former Bears starter Mitchell Trubisky and added offensive line depth in the draft with tackles Spencer Brown and Tommy Doyle. Brown has started five games at right tackle when the Bills have had injuries at guard and Daryl Williams has kicked inside to cover them. Other important 2021 additions include:

1. WR Emmanuel Sanders. Buffalo is one of the team's to benefit from the Saints' salary cap purge in the offseason, picking up a new starting receiver to replace the departed Jon Brown two days after Sanders was released by New Orleans. Sanders has started 11 games and is third on the team with 39 receptions and second with 581 receiving yards, averaging 14.9 yards per grab and scoring four total touchdowns.

2. P Matt Haack. Though he led the NFL with a 50.8 yard gross punting average in 2020, Corey Bojorquez was allowed to become a free agent and sign with the Rams (and later get traded to the Packers), while the Bills pivoted to Haack, the former Dolphin. Signed as an unrestricted free agent after four seasons in Miami, Haack has averaged 44.7 yards per punt, which happens to exactly match his career average.

3. DE Gregory Rousseau. The Bills made Rousseau the 30th player off the board in the 2021 draft, and the fourth edge rusher to be taken (fifth if we retroactively include Cowboys linebacker Micah Parsons). Rousseau has started every game for Buffalo and is second on the team with 3.0 sacks. The former University of Miami star has also contributed 41 tackles, six for losses, six quarterback hits and one interception.

ABSENCES/POTENTIAL ABSENCES

1. CB Tre'Davious White. Buffalo's defense suffered a significant loss on Thanksgiving when White, the two-time Pro Bowl cornerback, suffered a torn ACL on a non-contact injury against the Saints. In five seasons, White has already racked up 16 interceptions, 60 passes defensed, five forced fumbles and five fumble recoveries, but he will miss the remainder of this campaign. Second-year man Dane Jackson stepped into White's place in the starting lineup on Monday night.

2. G Jon Feliciano. Feliciano could actually become a key addition for the Bills this week, if the team chooses to activate him from injured reserve. Feliciano, Buffalo's stalwart left guard, has missed the last five games with a calf injury but was designated for return last week, meaning he's in the middle of a 21-day window in which he could return to the active roster. That could happen in time for Sunday's game in Tampa or the Bills could wait one more week.

3. LB A.J. Klein. Buffalo placed Klein on the reserve/COVID-19 list just hours before Monday's game against the Patriots, which could possibly jeopardize his availability for Sunday's game in Tampa. Klein had recently made two starts in place of injured linebacker Tremaine Edmunds, though Edmunds returned to action last week.