Vernon Davis inactive vs. Colts

SAN FRANCISCO -- San Francisco 49ers standout tight end Vernon Davis is inactive Sunday against the Indianapolis Colts due to a hamstring injury.

Davis will sit out his first game since 2007 after tweaking his hamstring late last Sunday at Seattle. Davis, who did not practice all week, did warm up prior to Sunday's game.

Davis tweeted Tuesday night that he expected to play. Because hamstrings are injuries that can get worse quickly, the 49ers are being cautious with their star.

San Francisco's next game is Thursday at St. Louis, which may have played a role in the decision to sit Davis.

Rookie Vance McDonald gets his first NFL start in place of Davis, one of quarterback Colin Kaepernick's favorite targets.

Davis will not be able to face his younger brother, Vontae Davis, who is a Colts cornerback. Sunday would have marked the brothers' first meeting since Vontae Davis entered the NFL in 2009.

San Francisco defensive lineman Ray McDonald (two sprained ankles) and safety Eric Reid (concussion) both are active and will start.