An MRI on Friday confirmed the Achilles tear, with a source telling ESPN's Adam Schefter that Barrett is expected to be out seven to nine months.
"It's a tough break for him," Bowles said. "Any time you lose somebody like that that commands double-teams, it makes it harder for everybody else. He's been consistent since he's been here. He's been productive. He started off playing well last night. It's just a shame to see."
Barrett was injured on a third-and-1 run play during the third quarter of Thursday's 27-22 loss to the Baltimore Ravens. After being attended to by athletic trainers, Barrett came off the field while barely putting any weight on his lower left leg and was carted off to the locker room once on the sideline.
The 29-year-old had three sacks in eight games this season, his fourth in Tampa Bay, but Thursday night might have been one of his best performances of the season -- with a sack, three tackles for a loss, four combined tackles and a 21.1% pressure rate prior to leaving the game.
The Buccaneers surrendered three touchdowns after Barrett left the game in the third quarter. He was replaced by Anthony Nelson, who had five sacks last season.
Nelson will continue to serve as Barrett's replacement, Bowles said, with Carl Nassib rotating in as well.
A two-time Pro Bowler, Barrett has been the Buccaneers' top edge rusher since his breakout season in 2019, when he led the NFL with an astounding 19.5 sacks. Barrett's 40.5 sacks are the fourth most of any defensive player since 2019, just behind Aaron Donald, as are his 12 forced fumbles.
Barrett's injury couldn't come at a worse time for Tampa Bay. The Buccaneers have dropped five out of their past six games and have fallen to a 3-5 record. Their once-top-ranked run defense has given up 632 rushing yards over the past four weeks -- the most in the NFL -- and the unit has struggled to pressure opposing quarterbacks.
Next week, the Bucs face the defending Super Bowl champion Los Angeles Rams, whom they have lost to three times since 2020, including a 30-27 loss in January that knocked the Buccaneers out of the postseason.