Gresham's injury is continuing to be evaluated, Oklahoma coach Bob Stoops said in a statement. Gresham, along with team doctors and athletic training staff, are considering treatment options that could have a bearing on his return.
Gresham tweaked his knee in practice Tuesday, according to reports. After strongly considering entering the NFL draft in April, Gresham -- the 14th-ranked NFL prospect in Scouts Inc.'s top 100 -- returned to school.
The 6-foot-6, 258-pound Gresham had 66 receptions for 950 yards and 14 touchdowns last season. He was a Sporting News First Team All-American last season and an Associated Press and Walter Camp second-team All-American.
Joe Schad covers college football for ESPN.