The Tampa Bay Buccaneers envisioned a deep rotation of defensive linemen in 2018, reminiscent of the Philadelphia Eagles' championship-winning group the year before, after hitting the position hard in both free agency and the draft. Free agency brought in two players from that Eagles rotation – Beau Allen and Vinny Curry – plus former Chicago Bear Mitch Unrein. That was followed by an impactful trade with the New York Giants for Jason Pierre-Paul and the selection of Vita Vea with the 12th overall pick in the 2018 draft.

The Buccaneers did get improved production from their defensive front, with 38 sacks in 2018 compared to a league-low 22 in 2017, but that deep rotation never materialized. Injuries were the culprit. Unrein missed the whole year and Vea was sidelined for the most of training camp and the first three weeks of the season with a calf injury. Allen, Curry and Gerald McCoy were all out with injuries of their own at various times, and though Pierre-Paul powered his way through all 16 games he was limited down the stretch by a wide variety of ailments.

A waiver claim that landed Carl Nassib just before the start of the season proved critical to the depth at defensive end, but the interior line in particular never got to utilize the rotational depth it had imagined. McCoy remained valuable with six sacks and Vea came on strong at the end of the season but there otherwise wasn't much production from the position.

A deeper rotation could emerge in 2019, however, depending upon Vea's continued development and how much the team gets from those 2018 additions and if the position gains any new faces from free agency or the draft. That's the big picture for the Bucs' defensive tackle position, but each player in that unit will face some specific questions of their own. In the weeks leading up to the new league year, we are going position by position and proposing one burning questions for each player on the 2019 roster. We started with a run through the offensive positions: tight ends, wide receivers, running backs, offensive line and finally the quarterbacks. Now, in the final week before the start of free agency, we're down to the last two spots on defense after previously discussing the safeties, cornerbacks and linebackers. We finish up with the front line of the defense this week, looking at the defensive tackles first and then moving on to defensive ends later in the week.

As will be the case at every position, we are only including players who are currently under contract for 2019, or could have tender offers as restricted and exclusive rights free agents. For the pending unrestricted free agents, obviously, the burning question that must be answered first is, 'Will they be back?'

One Burning Question for Each Buccaneer: Defensive Tackles

Players under contract for 2019: 6 (Beau Allen, Jeremiah Ledbetter, Gerald McCoy, Stevie Tu'ikolovatu, Mitch Unrein, Vita Vea)

Potential unrestricted free agents: 1 (Rakeem Nunez-Roches)

Potential restricted free agents: None.

Potential exclusive rights free agents: None.

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Beau Allen: How extensive will his role be in the Bucs' new defense?

When Allen signed with the Buccaneers in the early hours of unrestricted free agency last year, it looked like he would be the front-runner to start next to McCoy in the middle of the team's 4-3 front. That picture was muddied, however, when the team later selected Vea with its top draft pick. Allen did enter the regular season as the starter but that was at least partially due to Vea's long absence with the aforementioned calf injury.

Allen opened eight of the first 10 games, missing two due to injury. In late November, however, the Buccaneers put Vea into the starting lineup and he responded so well that he remained there for the last six games. Allen averaged just under 34 defensive snaps per game during his eight starts but only 19 per outing over the last six weeks. In the end, Vea had the more robust stat line, with 28 tackles, three sacks, four tackles for loss and four quarterback hits compared to 20, zero, two and three for Allen.

Still, Allen was a coveted target for the Buccaneers a year ago, in part because he had been such an effective run-stopper in a rotational role in Philadelphia. Sacks were never a big part of his output with the Eagles – two in four years – but he was still a valued contributor. He also just turned 27 in the middle of last season. The Buccaneers will have a new defense in 2019 under Head Coach Bruce Arians and Defensive Coordinator Todd Bowles, and some of the team's linemen will likely have different roles than in the past. It will be interesting to see how and how much Allen is utilized by the new staff.

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Jeremiah Ledbetter: Will his late season promotion in 2018 prove to be more than a cameo on the active roster?

Ledbetter, whom the Buccaneers signed to their practice squad at the start of the regular season, is coincidentally the son of a former draft pick of the franchise. In 1983, Tampa Bay selected Weldon Ledbetter in the seventh round but the Oklahoma tailback never got into a regular-season game for the Buccaneers or any other NFL team.

The younger Ledbetter has already surpassed his father in both regards, having played in 17 regular-season NFL games, including one last year for the Buccaneers. He was also a draft pick, going in the sixth-round to Detroit in 2017 out of Arkansas. Ledbetter made the Lions' roster and played in all 16 games as a rookie but was cut at the end of his second preseason in Detroit. The Buccaneers signed him to their practice squad and that one game in a Tampa Bay uniform came in the season finale after he was promoted in late December.

Ledbetter doesn't have much NFL production to speak of yet, with 14 tackles and half a sack for the Lions plus one stop in that last contest for Tampa Bay last year. But he does have a spot for a third consecutive training camp, as he heads into the 2019 offseason still under contract with the Buccaneers. McCoy and Vea look like the surest starting candidates – though in what sort of three or four-man line configuration is still to be determined – but there are likely to be some changes to that unit overall. With a strong enough camp, Ledbetter could get back on an opening-day roster, as he was two years ago.

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Gerald McCoy: What will we call McCoy in the Bucs' new defense?

This is Gerald McCoy in mid-January, presumably addressing the possibility that the Bucs' defensive front would be different under Bowles, and might lead to a somewhat different role for McCoy, who has been playing the three-technique in the Bucs' 4-3 front for the last nine years:

That's really all that needs to be said about McCoy being able to fit into what Arians and Bowles want to do on defense. Moreover, both coaches have stressed repeatedly that they will design their schemes around what the players on hand do best, and McCoy is still one of the Bucs' best players. At the NFL Scouting Combine last week, Arians compared a possible role for McCoy to what Darnell Dockett did in 2013 when he and Bowles arrived in Arizona. Even at his age 32 season, Dockett started all 16 games and produced 46 tackles, 13 quarterback hits and 4.5 sacks. McCoy, who just turned 31 late last month, has recorded at least five sacks in seven straight seasons, and at least six sacks in each of the last six years. There's no reason to believe he can't do even more than Dockett did in a similar role.

All that said, it will still be interesting to see how Bowles uses McCoy, whose greatest asset has always been his amazingly quick first step. McCoy will get some sacks based simply on his own talents, and Bowles has made it clear that the Bucs will remain a one-gap team up front, which means his pass-rush will be prioritized over taking on multiple blockers. McCoy may also find some additional opportunities to provide pressure if Bowles' aggressive schemes – which include not only the possibility of a blitz in any down or situation but also plays that look like blitzes but are really still four-man rushes – can confuse opposing offenses.

When the Cardinals first unveiled their 3-4 defense in 2013, they had Dockett listed as a "DT" but Dan Williams as the nose tackle, flanked by Dockett and "DE" Calais Campbell. Will McCoy be considered a DT if the scheme is similar, or an end? Will he always line up inside tackles or sometimes come off the edge? As he so succinctly noted on Twitter, it probably won't matter, but it will still be fun to find out.

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Stevie Tu'ikolovatu: Will he finally get a chance to play?

The Bucs used a seventh-round draft pick on the former USC defensive tackle in 2017 when they were making a concerted effort to get bigger and more stout up the middle against the run. Tu'ikolovatu had been considered one of the nation's best run-stopping linemen in college ball the year before.

Two years later, Tu'ikolovatu is still on the roster but the Bucs have yet to find out if he can actually help in that regard thanks to some particularly bad fortune on the injury front. First, he sustained a knee injury late in his rookie training camp and was sent to injured reserve for the entire campaign. He came back to a second Bucs camp this past summer but was felled once again, this time by a torn triceps in the middle of August. Once again, he spent the whole year on injured reserve.

When the Bucs do use traditional three-man fronts, Tu'ikolovatu could be a good fit for the nose tackle role, at least in a reserve role to spell Vea or when Vea plays the three-technique. First, however, Tu'ikolovatu needs better luck to make it to the end of the preseason in good health.

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Mitch Unrein: Where does he stand after missing the entire season due to a concussion suffered in training camp?

Unrein went into the concussion protocol after being injured in a practice early in training camp and never came out of it. The Buccaneers put him on injured reserve to start the season, and while there was a possibility the team could use one of two options to activate players from IR, that never materialized.

As noted above, Unrein was signed early in the free agency period and was part of that plan to have good rotational depth on the line during the regular season. He was seen as a linemen who could provide snaps both inside and outside, and that role could still materialize in 2019, but that necessarily comes second to the question of if and when he will return to the practice field for the Buccaneers. General Manager Jason Licht chose not to provide any specific details on Unrein's status when asked about the linemen at the Combine but said more information could be forthcoming within the next month.

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Vita Vea: Will his late-season surge be the springboard for a full breakout season in 2019?

Vea's debut campaign didn't start out particularly well but it ended on a strong note, and that's probably better than the reverse outcome. Vea's calf injury proved serious enough to keep him sidelined for all of camp andthe first three weeks of the regular season, and he was predictably rusty when he did finally get to suit up for games.

At the midway point of the 2018 season calendar, Vea had all of two tackles on his stat line. He had shown that he was capable of using his strength to move offensive linemen, but he was having trouble disengaging from those blockers and he wasn't making any notable plays. However, he collected his first NFL sack in Week 10 and two weeks later, after a practice-field pep talk from Licht helped clear his mind, he started on his six-week tear to end the season.

Over those final six weeks, Vea had 25 tackles, two sacks, four tackles for loss and three quarterback pressures. With a litany of injuries making it difficult for Pierre-Paul to keep up his own scorching pace, Vea was probably the team's most consistently effective D-Lineman over the last month or so.

Of course, none of that should have been particularly surprising. Vea is amazingly nimble and quick for a player listed at nearly 350 pounds, which is why he was so highly coveted in last year's draft. Had he not injured his calf on the third day of camp, he probably would have gotten into that six-week groove earlier in the season and his final rookie stats would be more impressive. As it is, that late surge now stands as a hint of what he is capable of doing on the NFL level. Will that come fully to fruition in 2019?