Coach Pat Shurmur said after Friday's practice that Pinkston is being treated for a blod clot, but provided no further specifics about Pinkston, a second-year guard from Pittsburgh. Several of his teammates visited Pinkston on Thursday night, and Pro Bowl tackle Joe Thomas said "it's a little bit scary" to see a teammate who is ill. Shurmur would not say where Pinkston's blood clot is located and he does not know how long the 25-year-old will be sidelined.
Pinkston started last week against Cincinnati but became ill and was replaced by John Greco, who played the entire second half. Greco will start on Sunday against Indianapolis. Greco played in 15 games for Cleveland last season after the Browns acquired him in a trade from St. Louis.
Pinkston started all 16 games in 2011 as a rookie. He played tackle in college, but was switched to guard last season after the Browns lost Eric Steinbach to a season-ending back injury.
The Associated Press contributed to this report.