Currently on the roster: Jacquies Smith, Robert Ayers, William Gholston, George Johnson, Howard Jones, Cliff Matthews, Martin Ifedi, Kourtnei Brown
The Bucs have had defensive end at the top of their list of needs since at least 2007, after Simeon Rice left -- and arguably well before that, when they struggled to get much out of players other than Rice. In all that time, they haven't found anyone capable of generating a sustainable pass rush. Last year, the Bucs knew they had to address the position -- and ended up trading for George Johnson, a player who had been at the bottom of their own roster just a year before. Incidentally, also a player who is now again at the bottom of the Bucs' roster.
The Buccaneers essentially have two types of defensive ends on their roster: heavier, base defensive ends who are likely to slide inside on passing downs -- if they're even on the field on those plays. The Bucs are actually very solid on that front. William Gholston is an outstanding run defender who flashes as a pass-rusher at times, and veteran Robert Ayers has had a lot of success in that role in the past. Cliff Matthews rounds out that group, but doesn't bring much as a pass-rusher. Regardless: while oversized defensive ends are useful, the Bucs have enough quality at that position.
The same can't really be said of the kind of edge defender every team wants: the explosive pass-rusher who can consistently beat offensive tackles. The Bucs have some young players with potential in Howard Jones and Jacquies Smith, who combined for 12 sacks last year. But those two weren't consistent players, struggled against the run and made very few plays outside of those 12 sacks.
That's a position the Bucs need to address, and they know it. They've had several defensive ends in for visits, including Noah Spence and Emmanuel Ogbah. The players we know they've focused on, have mostly fit the mold of the explosive edge rusher. But the Bucs have known for years that they need to find players like that, and for years they've failed to actually solve that problem.