SANTA CLARA -- Receiver Mario Manningham is expected to be sidelined for the 49ers' game Sunday against the Miami Dolphins with a right shoulder injury.
Manningham left the 49ers' game against the St. Louis Rams with the injury. He did not participate in any practices this week.
With Kyle Williams already out for the season with a knee injury and Manningham unavailable, it should open the door for first-round draft pick A.J. Jenkins to make his 49ers debut.
"I've seen progress from A.J.," 49ers coach Jim Harbaugh said. "He's been on his assignments. He's executed well when he's been out there. He's giving great effort, and football rewards effort."
Jenkins has suited up for just two games this season but has yet to play. Michael Crabtree, Randy Moss, Ted Ginn and Jenkins are the 49ers’ only healthy receivers for Sunday’s game.
Manningham is the 49ers' second-leading receiver with 41 catches for 449 yards and one touchdown.
Doubtful: WR Mario Manningham (shoulder)
Probable: K David Akers (pelvis), LB Navorro Bowman (shoulder), CB Tarell Brown (hamstring), CB Chris Culliver (illness), LB Tavares Gooden (knee, elbow), RB Frank Gore (wrist), G Mike Iupati (shoulder), CB Carlos Rogers (knee), LB Aldon Smith (shoulder), LB Patrick Willis (shoulder)
Questionable: S Jimmy Wilson (hip)
Probable: TE Charles Clay (ribs), LB Karlos Dansby (biceps), TE Anthony Fasano (hip), P Brandon Fields (left knee, right knee), RB Jorvorskie Lane (knee), LB Koa Misi (finger), LB Austin Spitler (ankle)