Offensive lineman Anthony Davis’ week-old concussion will keep him out of a second straight game, when the 49ers visit the Seattle Seahawks on Sunday.

The 49ers could also be without one of their top defensive backs in Jaquiski Tartt, who was limited in practice all week with a right-knee injury. Tartt is listed as questionable, as is defensive back Marcus Cromartie (ankle).

The Seahawks did not rule anyone out but running back Thomas Rawls (shin) is listed as doubtful, along with guard Germain Ifedi and tight end Nick Vannett. Rawls rushed for 209 yards in Seattle’s 29-13 home win last season over the 49ers.

Davis sustained the concussion in practice on Sept. 15, and coach Chip Kelly said Thursday he did not see how it occurred but only that it happened during the padded period. Davis played only the final three snaps of the season opener after skipping the previous Saturday’s practice while pondering his future.

Expected to play are defensive linemen Arik Armstead (shoulder), Quinton Dial (knee), Glenn Dorsey (knee) and Mike Purcell (ankle); cornerback Keith Reaser (ankle); right guard Andrew Tiller (ankle); and linebacker Nick Bellore (knee).