There are currently 5 linebackers on the roster, two of whom have never gotten on the field as a special teams player let alone as a regular player for the Bucs. Those two players are J.D. Folsom and Simoni Lawrence, and it'll be a small miracle if they start to make an impact on any down next year. The Bucs have just 3 players under contract who could start: Geno Hayes, Tyrone McKenzie and Dekoda Watson. Geno Hayes has several years of experience now and is a bit of an up-and-down player, but he's especially strong in coverage and a valuable starter. Tyrone McKenzie is largely unknown, but the coaching staff seems to like him and he was a 3rd-round pick for the Patriots in 2009. Finally, Dekoda Watson looked decent when he was on the field late last season, but he's hardly a great starter. The Bucs lack talent at the linebacker position, but they lack depth even more.
So what are the Bucs going to do? Well, it'll all depend on who falls to them in the draft. If they come out of the draft with three linebackers, they could go forward with those three and the three linebackers they have on the roster. Then they could let a training camp competition sort it all out. But if they don't come out of the draft with several linebackers, they need to start re-signing their own free agents in Barrett Ruud, Quincy Black and Adam Hayward. Failing that, they should look to free agency to find the players they need.
But this shows the way the lack of free agency affects the draft: the draft will now determine the Bucs' free agency strategy, instead of the other way around.