Coach Kevin Stefanski didn't have much information on Cooper, who underwent surgery to repair a core muscle injury during the offseason. Cooper was on the field during the portion of practice open to the media.
Stefanski said Cooper was taken inside for treatment by trainers before practice ended.
“We’ll see how he does over the next 48 hours,” Stefanski said.
Cooper led the Browns with 78 catches for 1,160 yards and nine touchdowns last season, his first in Cleveland after four with the Cowboys and four with the Raiders. He played the final weeks of 2022 despite the core muscle injury.
Cooper briefly came into the locker room following practice but didn't talk to reporters before leaving.
The 29-year-old Cooper is a major part of Cleveland's offensive attack and not having him in Pittsburgh would be a huge blow to the Browns (1-0), who are coming off a 24-3 win in Week 1 over Cincinnati.
Cooper left the field in the first half against the Bengals with an apparent knee injury, but said earlier this week he had just “tweaked” something and was fine. Cooper finished with three catches for 37 yards as the Browns won their first home opener since 2004.
Cooper's injury could deprive quarterback Deshaun Watson of his top target and would mean receivers Elijah Moore, Marquise Goodwin, Donovan Peoples-Jones, David Bell and rookie Cedric Tillman may have larger roles.
“We don’t know exactly what happened to him,” Moore said. “I don’t think we should be speaking on anything before we know anything, but it's annoying when you have little mishaps like that. That’s football.
“I feel like we got a group to where everyone should know everything. I’m pretty confident in every last one of those guys.”
Starting safety Juan Thornhill is also listed as questionable with a calf injury that kept him out of the opener. He returned to practice this week for the first time since Sept. 6.
The Browns haven't won a regular-season game in Pittsburgh since 2003.
AP NFL: https://apnews.com/hub/nfl