SANTA CLARA, Calif. -- The San Francisco 49ers activated wide receiver Mario Manningham and cornerback Eric Wright on Monday and placed cornerback Nnamdi Asomugha on waivers.

Manningham came off the physically unable to perform list and Wright came off the non-football injury list. Both players had to be activated this week as their 21-day practice window was expiring. The team entered the day with 52 players on the roster.

Both players are expected to help San Francisco immediately. Manningham may have the biggest impact and likely will start for the 49ers, who have gotten virtually no production at receiver beyond Anquan Boldin. Manningham had 42 catches for the 49ers last season before suffering a knee injury in December.

Manningham will give the 49ers relief as they continue to wait on standout receiver Michael Crabtree to rerun from a torn Achilles. He is expected to be back in the next month or so.

Wright was signed in the offseason to bring experience and ball skills to the defending NFC champions, and he will add to an already strong secondary. The cornerbacks have played well during the 49ers' five-game winning streak.

The starters are Carlos Rogers and Tarell Brown, and Tramaine Brock has taken over as the nickel cornerback from Asomugha. Brown is reportedly getting close to a contract extension.

Asomugha, once considered one of the top cornerbacks in the NFL, signed with the 49ers this offseason after his release by the Philadelphia Eagles, just two seasons after signing a five-year, $60 million contract.

He has just two tackles this season and hasn't played since Sept. 22.

The 49ers initially acquired Wright from the Tampa Bay Buccaneers before training camp, but the trade fell through when the team failed him on a physical examination. Wright then later signed with San Francisco after he was released by Tampa Bay.