SAN JOSE – Quarterback Colin Kaepernick finally is able to lean into his throws, and the results have swept his receivers off their feet.

Literally.

Early in Tuesday's player-run 49ers practice at San Jose State, Kaepernick dropped back and fired a dart to wide receiver Lance Long that was traveling so fast it knocked Long, who was coming out of his break, on his backside.

"I had a few receivers come and tell me that I've been throwing it pretty good," a smiling Kaepernick said after the session. "I think you just get used to seeing the different flights of different quarterbacks' balls. Some of those guys haven't caught my balls yet, so it's just something they're getting used to."

Kaepernick's big right arm was one reason the 49ers made him a second-round draft pick in April. Until recently, however, he hasn't been able to show it off.

He had surgery on his lower left leg in early May, and when the 49ers' offensive players assembled the first week of June, Kaepernick still was recovering. He participated in warmups during that initial minicamp but yielded to fellow quarterbacks Alex Smith and David Carr when practices began.

Kaepernick said he still hasn't been given the "green light" by his doctors – high-impact movements such as jumping still are forbidden – but that he has been cleared to drop back and put as much zing as he wants into his throws.

"I definitely have to get back a little of the timing, get back to the pace of the routes, the timing of certain things," he said. "I mean, that's just going to take a little bit of time.

"But for the most part, I felt like I was on time with most of my throws today and felt good out there."

Kaepernick handled roughly a third of the practice throws Tuesday. Offensive tackle Joe Staley said he and the other veterans were impressed with the rookie's command.

"He doesn't have that rookie, deer-in-the-headlights mentality," Staley said. "I think he's going to be a good quarterback. The ball comes off his arm pretty fast. He's a real, real intelligent kid. I think he'll pick up this offense pretty quickly."

Twenty offensive players were on hand Tuesday, approximately the same number that participated in the players' June 6-9 camp. Seven wide receivers, including Michael Crabtree, were part of the group.

Crabtree also attended the earlier minicamp but participated only in the June 6 practice. According to teammate Josh Morgan, Crabtree suffered sore feet after wearing new cleats during that practice. He did not engage in any of the other practices that week for fear he would aggravate his left foot, which required surgery before the 2009 draft.

Crabtree still was taking it easy on the foot Tuesday.

He caught a few light passes during warmups but didn't run any routes at full speed. When practice began, he stood by the quarterbacks and referred to a copy of the practice script.

Kaepernick, wide receiver Ronald Johnson and guard Mike Person were the only rookies at the minicamp. Others from their draft class, including running back Kendall Hunter and fullback Bruce Miller, are attending a rookie symposium this week in Florida.

The only offensive starters from 2010 who were not on hand were running back Frank Gore, center David Baas, right guard Chilo Rachal and right tackle Anthony Davis.

Anthony Dixon filled in at running back, Adam Snyder played center, Person played right guard, and Alex Boone lined up at right tackle.

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