49ers star LB Fred Warner (lower leg) exits vs. Bucs

San Francisco 49ers star linebacker Fred Warner was carted off the field midway through the first quarter of Sunday's road game against the Tampa Bay Buccaneers with a potentially serious right lower-leg injury.

Warner was defending a running play when his right leg got caught up from behind by pursuing teammate Ji'Ayir Brown. Warner's right foot appeared to be pointing in the wrong direction before an air cast was placed on the leg by trainers.

Warner, in his eighth season, is the leader of the San Francisco defense.