San Francisco 49ers wide receiver Isaac Bruce, who has dealt with a bad ankle for most of the season, rolled it during practice and is questionable to play in Thursday night's game against the Chicago Bears.
Bruce, who was injured Tuesday, would be replaced by third-year pro Jason Hill if necessary, 49ers coach Mike Singletary said Wednesday.
"He was doing fine," Singletary said of Bruce. "He was trying to work his way through it. Yesterday, he rolled it."
Bruce, a 16-year NFL veteran, has caught 20 passes for 244 yards this season. He has 1,023 receptions and 91 touchdowns in his career.
Hill also has been bothered by an ankle problem.
Running back Glen Coffee (concussion) is out, and safety Michael Lewis (quad), tight end Vernon Davis (shoulder), tight end Delanie Walker (knee) and linebacker Takeo Spikes (shoulder) are probable.
The Bears could be without rookie safety Al Afalava, who missed practice all week with a shoulder injury. Afalava is listed as questionable.
The Associated Press contributed to this report.