SANTA CLARA — Tight end Vernon Davis is inactive for the San Francisco 49ers against the Kansas City Chiefs because of a back injury.
Backup tight end Vance McDonald is in the lineup Sunday after missing the past two games with a knee injury.
Right tackle Anthony Davis also is inactive for the 49ers because of a banged up left knee. Jonathan Martin will make his fourth start of the season in Davis' place.
Cornerback Marcus Cooper is starting for the Chiefs. He had been questionable all week with a knee injury.