ST. LOUIS (AP) -- St. Louis Rams starting safety T.J. McDonald injured a leg Thursday night against San Francisco.
Trainers immediately put an air cast on McDonald's right leg, and he was carted off.
McDonald, a rookie third-round draft pick out of USC, appeared to run into defensive end Gerald Rivers at the end of a 3-yard run by the 49ers' Frank Gore in the third quarter.
St. Louis cornerback Cortland Finnegan sustained a thigh injury in the second quarter and his return was doubtful. Finnegan was hurt covering Anquan Boldin on a 20-yard touchdown pass from Colin Kaepernick 6:20 before halftime.
San Francisco backup wide receiver Quinton Patton's return was questionable after a first-quarter foot injury.