Kyle Williams is out for the season with torn ACL in his left knee, an injury that forces the San Francisco 49ers to shuffle personnel at multiple spots.
Williams splits return and wide receiver assignments with Ted Ginn, averaging 27.2 yards on 13 kickoff returns and 13 yards on four punt returns. He caught 14 passes for 212 yards and one touchdown working mostly in multiple-receiver packages.
The 49ers are varied in their offensive formations and can rotate enough receivers and tight ends to fill Williams' role as a receiver. But Ginn and rookie first-round pick A.J. Jenkins, who hasn't logged a snap in any game this season, are likely to see increased chances in the base offense.
Head coach Jim Harbaugh places a premium on special teams. It's likely the 49ers will audition veteran options to replace Williams.
Kendall Hunter has returned kickoffs but was also injured Sunday, meaning rookie LaMichael James might be active at St. Louis. The speedster could fill multiple roles as a returner and backup running back.