SANTA CLARA, Calif. -- The San Francisco 49ers are set to get some much-needed relief at receiver.Mario Manningham is expected to start practicing this week. The team will have three weeks to activate Manningham. He has been out all season with a knee injury he suffered last December.The 49ers badly need more production from their receivers. Their only true passing-game weapons this season have been Anquan Boldin and tight end Vernon Davis. The team also hopes to get standout Michael Crabtree back from a torn Achilles, perhaps as early as Mid-November.