ST. LOUIS — San Francisco 49ers running back Frank Gore, hampered by a sprained left ankle, was inactive for the second straight week Sunday.

Gore needs 22 yards to become the first 49ers player to rush for 1,000 yards in three consecutive seasons. DeShaun Foster started in place of Gore for the second straight week after gaining 76 yards on 18 carries last week in a loss to the Dolphins.

Backup running back Antonio Pittman was inactive for the Rams. Pittman has fallen behind Kenneth Darby on the depth chart.