49ers injury report: Crabtree limited

San Francisco 49ers receiver Michael Crabtree, who sat out Wednesday with a calf issue, returned to the practice field Thursday in a limited capacity.

Dallas native Crabtree, who is gearing up for a homecoming against the Cowboys, dealt with a sore hamstring in training camp.

Also, cornerback Chris Culliver (ankle) and tight end Vance McDonald (hamstring) appeared on the 49ers' second injury report of the season as both practiced limited.

Right tackle Anthony Davis (hamstring) and rookie backup center Marcus Martin (knee) both missed practice for the second consecutive day. Martin has essentially been ruled out for six weeks after being injured in the third exhibition game, and Davis' streak of 64 straight starts is in jeopardy.

Davis underwent shoulder surgery in the offseason and said after camp broke he did not need an exhibition game to play in the season opener.