SANTA CLARA -- Wide receiver Kyle Williams, out since late November with a knee injury, officially entered the competition to replace Michael Crabtree on Thursday.
A.J. Jenkins, Quinton Patton and Ricardo Lockette got most of the offseason practice snaps as the split end after Crabtree sustained a torn right Achilles tendon on May 21. The 49ers are hoping Crabtree can make a late-season return.
Williams was removed from the active physically unable to perform list on Thursday in time for the 49ers' first practice of training camp.
Veteran Anquan Boldin figures to be the 49ers' top wide receiver from the flanker position. On the other side, there are not any players who have experienced a lot of NFL success.
Williams caught 14 passes last season before he sustained a torn ACL in his left knee. Neither Jenkins nor Lockette caught a pass a year ago, and Patton is a rookie. Marlon Moore, who made a good impression in the offseason program, caught six passes for the Miami Dolphins.
Many figure the 49ers are thin at wide receiver, but Williams believes there is a lot of unknown talent on the depth chart.
"They can say that all they want," Williams said. "We don't feel like that in our room at all. And I don't think the rest of the guys in our locker room feel that way, either. They know what we have here. We know what we have here."
At some point, Mario Manningham will return from a knee injury of his own. Manningham, who was second on the team behind Crabtree with 42 receptions last season, figures to be about a month away from making a run at getting on the field. In any event, it'll probably take more of a committee approach to compensating for the loss of Crabtree.
"Losing a guy like 15 (Crabtree) is going to hurt," Williams said. "It's definitely going to hurt. You're not going to replace a guy like that. You're not going to plug somebody in and do the same types of things. He's an elite receiver. So we're going to have to pick up the sack. That's all of us."
The competition among the wide receivers figures to be one of the most compelling storylines of training camp. And quarterback Colin Kaepernick is as eager as anyone to see how it shakes out.
"It's a tragic situation that happened to a great player like Crab," Kaepernick said. "People are going to have to step up. Who that is will really depend on how this camp goes."