Denver Broncos wide receiver Tim Patrick and running back Damarea Crockett sustained apparent knee injuries during Tuesday's practice, NFL Network reported.
Per the report, the Broncos fear that both players suffered significant injuries.
Patrick, 28, was hurt when he landed awkwardly after making a twisting, leaping catch.
Broncos players, including quarterback Russell Wilson, huddled around Patrick before he was carted to the locker room.
Patrick started all 16 games he played last season, catching 53 passes for 734 yards and five touchdowns.
In 55 games (37 starts) for the Broncos over the past four seasons, the Utah product has 143 catches for 2,009 yards and 12 touchdowns. He led Denver in TD receptions in each of the past two seasons.
Crockett, 24, rushed three times for seven yards in 12 games last season.
--Field Level Media