Adams, the fourth overall pick in the 2007 draft, had been a disappointment in his first two seasons under coach Jon Gruden. He was supposed to get a fresh start under coach Raheem Morris. Defensive coordinator Jim Bates spent much of the offseason working on pass-rush moves with the defensive end.
Morris singled out the 6-foot-5, 258-pound defensive end on the opening day of training camp, saying Adams would be considered a "bust" if he didn't post double-digit sacks this season.
But Adams had one sack and 10 tackles in Tampa Bay's first three games. That apparently caused the Bucs to give up on Adams as they go through a rebuilding process. Adams had six sacks as a rookie and 6 1/2 last year.
On Saturday, the Bears released veteran tight end Michael Gaines to accommodate Adams on the 53-player roster.
Adams likely will play against Atlanta on Sunday night because defensive linemen Anthony Adams and Israel Idonije are dealing with injuries. The move also could provide insurance in the event Adewale Ogunleye and Mark Anderson leave via free agency at the end of the season.
NFC South blogger Pat Yasinskas and The Associated Press contributed to this report.