NFL Network's Ian Rapoport reported Tuesday that an MRI confirmed the ruptured Achilles as well.
The 2019 season was a disappointing one for the 24-year-old Howard. The 2017 first-round pick was on his way to a breakthrough year in 2018, catching 34 catches for 565 yards and five scores in 10 games and showing the potential that made him a high draft selection.
But foot and ankle injuries ended his season that November. And that disappointment lingered into 2019.
Howard didn't keep his pace from 2018, managing just 34 receptions for 459 yards and a score in 14 games.
Injuries are also becoming a recurring concern. A hamstring issue kept him out of the team's Week 8 matchup with the Tennessee Titans last year, and now he's dealing with a major injury.
The Bucs do have solid depth at the position, however, with Rob Gronkowski and Cameron Brate available with Howard gone for the remainder of the campaign.