The Bucs have cut reliever Romulo Sanchez:

Neal Huntington declined to get into specifics, but he did say this: "He's got a lot of delivery work to do, and we felt that it was best that he do that outside of major league camp, with the way he came into spring training. He's got a great arm and still has a future with us, but he'll have to work his way back to the majors. He wasn't in line to make this club."

The key phrase there is "with the way he came into spring training." The Post-Gazette connects that of Josh Sharpless last year, in which Huntington explicitly said he was cutting Sharpless because Sharpless didn't show up in shape for camp. 

As for the other three cuts (pitcher Daniel Haigwood, catcher Miguel Perez and infielder Pedro Lopez), I'm not sure if there's a reason they're being cut this early, beyond the obvious one that none of them had any prayer of making the big-league team.