Foster will undergo back surgery next week and miss the rest of the season. Ben Tate, still recovering from four broken ribs, is expected to start Sunday at Arizona. Dennis Johnson and Deji Karim, who were both signed last week, will play behind Tate.
Foster didn't practice all week after injuring his back on Houston's first series against Indianapolis last Sunday. He also missed most of Houston's previous game with a hamstring problem. Interim coach Wade Phillips said Friday that Foster had visited specialists about the problem. The Pro Bowl player gained 542 yards on 121 carries with one touchdown and had 22 receptions and another score.