The NFL's 2018 unrestricted free agent market opens next Wednesday, and the Tampa Bay Buccaneers just might go shopping. Here are a few things you need to know in order to follow along.

1. The new league year begins on Wednesday, March 14 at 4:00 p.m. ET

That's the starting gun for free agency because the end of the 2017 league year means the expiration of all player contracts that did not extend past that season. If the final list of names that make it to free agency is similar to last year, there will be around 500 players for teams to consider, although a small percentage of those will be restricted free agents (more on that below).

Of course, there is always an upper tier of highly-coveted free agents, a much smaller group that will garner 95% of the attention in the first week of the open market. Many of those players will sign very quickly after free agency officially begins, and that's because…

2. A lot of groundwork for the opening hours of free agency will be put in place next Monday and Tuesday, and before the 4:00 p.m. kickoff on Wednesday.

Since 2013, the new league year has been preceded by a 48-hour window in which there can be discussions about, but no execution of, potential contracts for impending free agents. Teams are allowed to contact the certified agent of a player whose contract is about to expire, and they can work on the framework of a potential deal. They may not actually make a contract offer, nor may they actually speak with players or set up plane flights for visits.

The fact that, virtually every year, several big deals are announced just minutes after the 4:00 p.m. start, makes it clear that a team and a player can use this window rather effectively, even if the official work can't commence until the new year begins. Of course, teams have been studying potential lists of free agents for much longer than 48 hours, and in doings so they knew that…

3. Once the actual free agency period begins, there will be three types of free agents on the market…or really only just two. Unless you count it as four.

Most of the 500-or-so free agents will fall into the unrestricted and restricted categories. Players who have accrued four or more seasons of free agency credit (basically, they've played in or been on a list like injured reserve for four seasons) are unrestricted, meaning they are immediately free to sign with any team they choose without compensation returning to their previous team. Since all players drafted from the second round on now get original four-year deals, this list includes a lot of players who are just finishing their first NFL contracts and are still in their mid-20s. First-round picks get four-year deals with a fifth-year team option, and some of them will hit the market on Wednesday as well. These tend to be the more coveted players because they have a better shot at returning value for the length of a multi-year contract.

Restricted free agents are hitting the market with three accrued seasons and they are not exactly free. If they receive a qualifying offer from their original team before the start of free agency, they have some, well, restrictions on their options. Depending upon the size of the qualifying offer, a signing team may have to send a draft pick back to the original team if they snap up a restricted free agent. In addition, the qualifying offer gives a restricted free agent's original team a chance to match the new contract offer. As such, the vast majority of restricted free agents sign their one-year tender offers with the goal of becoming unrestricted the next year.

There is also a class of players under the "exclusive rights free agent" header, though that term is a bit oxymoronic. These players can also get pre-free agency qualifying offers, and if they do they can only negotiate with their original team. That's not really free agency, but it is the beginning of the multi-year process for these young guys. Any restricted or exclusive rights free agent who does not get a qualifying offer hits the open market without restrictions.

The other type of free agent is a subset of the unrestricted group and has been the subject of much media attention the last two weeks. Perhaps you've noticed that…

4. Seven attractive free agent targets who might have hit the open market have instead been given franchise or transition tags.

Teams had a two-week window, beginning on February 20, in which they had an option to place a franchise or transition tag on a pending unrestricted free agent. These tags make it either impossible or much harder for a player to sign with another team, depending upon the "level" of the tag that is used, though they do carry with them very lucrative one-year salaries. Teams often use the tags as an attempt to lengthen the amount of negotiating time they have with a player they would like to sign to a new long-term deal.

Six teams chose to use a franchise tag: Cincinnati on tight end Tyler Eifert, Dallas on defensive end Demarcus Lawrence, Detroit on defensive end Ezekiel Ansah, the Los Angeles Rams on safety Lamarcus Joyner, Miami on wide receiver Jarvis Landry and Pittsburgh on running back Le'Veon Bell. The Chicago Bears used a transition tag on cornerback Kyle Fuller. There's no telling if the Buccaneers would have had serious interest in trying to sign any of those players, but it's reasonable to argue the team could use help at a couple of the positions represented by that group, particularly defensive end. Whether or not the Bucs would have gone after someone on that list, the tags have somewhat weakened the potential open market at several spots.

There are two types of franchise tags, exclusive and non-exclusive. The exclusive tag means a player cannot negotiate with any other teams. The non-exclusive tag carries a slightly lower salary burden but allows players to negotiate with other teams. Even so, that rarely happens because a team that signs a player with a non-exclusive franchise tag must send two first-round picks back to the original club. The transition tag kept the door open a little wider for Fuller and a potential departure, as a signing team would not have to send back draft-pick compensation.

Even with those seven players off the board or restricted in their movement, there should be plenty of open-market action on Wednesday and the weeks that follow because…

5. There is potential help available for shopping teams at just about any position.

This is where we drop the usual caveat about the musings on this page having nothing to do with the free agency strategy or player evaluations of Buccaneers General Manager Jason Licht, Head Coach Dirk Koetter or any of the team's actual player-personnel decision-makers. They undoubtedly have a thorough action plan ready for free agency, with multiple contingencies, but they won't be sharing that with anyone outside the building. Any names you see below are strictly from outside sources evaluating the players expected to hit free agency.

In fact, in this case, let's use the list of the top 101 pending free agents in the opinion of NFL.com's Gregg Rosenthal and Chris Wesseling. The most notable thing about this list is that there are two quarterbacks at the top of it, though most analysts expect New Orleans to get Drew Brees re-signed without real exposure to the market. Still, with Kirk Cousins expected to leave Washington in the wake of the Alex Smith trade and the likes of Case Keenum, Teddy Bridgewater, Sam Bradford, A.J. McCarron and Josh McCown on the Rosenthal/Wesseling list, this could be an unusually active free agency period for viable veteran passers.

Need offensive linemen? The NFL.com duo thinks highly of Carolina's Andrew Norwell, New England's Nate Solder and the Giants' Justin Pugh. There are four cornerbacks in the top 15 of that list, though one of them is Fuller, and the tag complicates matters. The Ansah and Lawrence tags diluted the edge-rushing pool but Rosenthal and Wesseling like a couple interior linemen in Dontari Poe and Sheldon Richardson. Neither Allen Robinson nor Sammy Watkins got tagged so NFL.com put them in the top 10 on their list.

There is also a player who was a Buccaneer for the past two seasons in the top 40 on that list, but only one because…

6. Tampa Bay's list of their own pending free agents, isshorter than it was a year agoand features only a couple full-time 2017 starters.

That top-40 player is cornerback Brent Grimes, who is a player the Buccaneers would like to have back. Grimes said at the end of the 2017 season that he would take some time to think about his next move, but nothing has happened yet and he is set to become a free agent on Wednesday. Rosenthal and Wesseling put him at #39 on their list.

The other primary starter on Tampa Bay's list of pending unrestricted free agents is left guard Kevin Pamphile. Defensive end Will Clarke, quarterback Ryan Fitzpatrick, cornerback Robert McClain, defensive tackle Clinton McDonald, guard Evan Smith and safety T.J. Ward all logged some starts in 2017 as well and are apparently headed for the market. Licht indicated at the NFL Scouting Combine last week that the team has interest in bringing Fitzpatrick back.

That could happen before or after the starting bell of free agency. For the most part, the Buccaneers probably don't have a lot they need to get done on their own side before next week because…

7. The team prepared for the annual spring rite of recharging the roster by making a series of tweaks over the last month.

On Wednesday, the Buccaneers exercised 2018 option contract years on three veterans: tackle Demar Dotson and safeties Chris Conte and Josh Robinson. That's the kind of roster work that often gets done in the week leading up to the beginning of free agency. Since the Buccaneers still have exclusive negotiation rights with their pending UFAs for a few more days, they could attempt to get a deal or two done before next Wednesday. A year ago, for instance, the team re-upped with defensive end Will Gholston two days before the market opened.

Prior to that, the Buccaneers did what just about every team does every year and made some moves that streamlined the roster for the start of free agency and had some effect on their available salary cap space. As noted, Doug Martin was released. So was defensive tackle Chris Baker, a 2017 free agent signing that did not produce great results. Kicker Nick Folk got cleared medically and was subsequently released, as the Bucs were obligated to do. A few young prospects, like Crossan and former CFL standout linebacker Jeff Knox, filled in a gap or two on the offseason roster.

The Buccaneers began the 2018 offseason with plenty of room under the salary cap and then created a little bit more. This space could be used to bring in outside free agents or lock down some of their own young talent…or, most likely, both. There's reason to believe Tampa Bay will make use of the free agent market, whether in big ways or small, because…

8. The Buccaneers haven't sat out free agency in a while.

Last year, the Bucs came out of the gate quickly with Baker and wide receiver DeSean Jackson, then added McClain and J.J. Wilcox to the secondary a little later. The 2016 free agency period brought in Bryan Anger, Robert Ayers, Josh Robinson and J.R. Sweezy.

In fact, the Bucs have dipped into unrestricted free agency several times in each of the previous four years that Licht was in the G.M. chair. As is often the case in veteran free agency, some of the team's additions have helped quite a bit and some haven't really worked out. That happens across the league, every year, and yet teams still come back to the well because there are a limited number of ways in which they can add to their roster. Every NFL franchise stresses the need to build through the draft, but sometimes free agency is necessary as a supplement.