Over the past few weeks, there have been large discrepancies between the 'official' NFLPA salary cap space report, and the independent estimates of places like Over The Cap, probably because of administrative delays in filing contract details. No, more however: both the NFLPA and Over The Cap have the Bucs at slightly over $12 million in cap space. That's before the Louis Murphy signing, but he shouldn't be much more expensive than the veteran minimum.
That doesn't mean the Bucs have $12 million in space left to spend, though. There's really no one they could spend that kind of cash on, anyway -- DeSean Jackson and Alex Mack are not realistic options and Gerald McCoy's extension shouldn't increase his cap number this year. They could add some depth (and probably should do so), but no one expensive is even available at this point. Even if they had that money, they couldn't really spend it.
No, the problem is that the Buccaneers need a significant amount of cap space to operate during the season. Incentives will hit the cap, as will some per-game bonuses, they'll need to pay their practice squad players, sign their rookie draft picks, and they will need to sign replacements for the inevitable injuries. This can add up quickly. As an example, the Bucs were sitting on a whopping $18.23 million in cap space by July of last year, but they ended the season with just $6.8 million. That's a difference of $11.4 million.
That's a bit of an extreme case, but you do need some space to work during the season. One example of how this happens is Connor Barth. After a restructure last season, he counts for $2 million against the salary cap right now. However, he can earn $1.15 million in per-game roster bonus, which will hit the cap as they occur. Of course, Barth may become a cap casualty with time and they could create more space by replacing Michael Koenen, too. But those are eventualities, and not realistic options until they've added those replacements.
Overall, I'd give a rough estimate that the Buccaneers have some $5 million they can safely spend this offseason. They will need $3 million to sign their rookie draft picks (per Over The Cap), they'll need another $1.15 million for Connor Barth, around $1.5 million to pay their practice squad players and the 52nd and 53rd players on the roster (in the offseason, only the top 51 contracts count). That's a minimum of $5.65 million we can subtract from the $12 million they have available, and that's before they have to sign injury replacements. Oh, and we're not counting Louis Murphy yet.
$5 million may even be a conservative estimate, but they can cut a few players to make more room. Regardless, one thing is clear: the Bucs are basically done spending at this point.