According to Cleveland.com's Mary Kay Cabot, Garrett is scheduled to undergo further evaluation and is likely to have an MRI.
Citing a source, Kay Cabot reported "the Browns are worried the injury could sideline him for weeks."
Garrett previously gave Browns fans a scare during minicamp when he suffered a foot injury.
The No. 1 overall pick also dealt with an ankle sprain during his final season with the Texas A&M Aggies that limited his impact on the field. Garrett still finished the year with 15.0 sacks and 8.5 tackles for loss.
While Cleveland is unlikely to be a playoff contender, expectations will be high for Garrett in his first year since he was the consensus best player in the 2017 draft class. Especially after Courtney Brown and Tim Couch—the Browns' most recent No. 1 overall picks—were largely busts, any problems he has will likely be magnified by the fanbase.
The Browns defense will be worse without Garrett, but Emmanuel Ogbah ensures the defensive line has at least one talented pass-rusher. Ogbah finished with 5.5 sacks as a rookie in 2016.