SANTA CLARA It looked like the sort of play that could flip the script for A.J. Jenkins, who badly needs some momentum after a dud of a performance in the 49ers' preseason opener Thursday against Denver.
The speedy wide receiver lined up far to the left of Colin Kaepernick in the Monday afternoon practice and took off downfield on a post pattern. Jenkins had a step on undrafted rookie cornerback Darryl Morris, and Kaepernick let fly a 45-yard pass that seemed as if it would hit Jenkins in stride.
At the last moment, however, Morris accelerated and batted away the ball for an incompletion.
That was theme of Jenkins' afternoon. He went through the session without catching a pass, and he appears to be lagging behind in the team's crowded wide-receiver competition.
If Jenkins needs a confidence boost, he can turn to teammate Vernon Davis. Asked Monday which wideouts have caught his eye, Davis concentrated on one.
"I really like A.J. Jenkins," he said. "He's got a lot of potential. He's still learning the game He has all the potential to do it. It's just taking him a little time, but he will get there. And I think he will be prepared by the start of the season."
Davis said there's no reason to rush Jenkins, the team's first-round pick a year ago who went through his rookie season without a catch.
"He's got time. He's got time," Davis said. "I don't think we can rush him, because it's up to him to change his mindset and really take off. Not only change his mindset, but really grasp whatever it is the coaches are trying to give to him, whichever role it is, and blossom. I think he has it in him."
Indeed, Jenkins has three more preseason games to recapture momentum and the backing of increasingly frustrated fans. But his practice opportunities aren't as abundant as they were earlier this month.
In the week leading up to Thursday's game, Jenkins got more practice snaps than any other wide receiver, and he was in on more plays, 39, than any other receiver against Denver.
Those opportunities have been curtailed over the last two practices as previously injured players such as veterans Kyle Williams and Kassim Osgood have gotten worked into the mix and newcomers such as Austin Collie and Lavelle Hawkins have received more snaps.
Hello, old friend On Sunday, offensive coordinator Greg Roman joked that the 49ers would treat Kansas City quarterback Alex Smith, whom the 49ers will face Friday, like any other "nameless, faceless" opponent.
The next day, coach Jim Harbaugh said Smith was anything but.
"It's personal with Alex," Harbaugh said. "It's different in that way. And I feel like there's a great friendship there and a lot of history. He's a unique person. He's a good friend. And he's no longer on our team, not a trusted agent anymore. I know what a competitor he is. He wants to win, and we do as well."
Smith is expected to play more than the one series he ran in the Chiefs' preseason opener last week.
Injuries One starting cornerback, Tarell Brown, was back at practice, but another, Carlos Rogers, was out with an apparent hamstring strain. As forecast by defensive coordinator Vic Fangio, Brown spent a lot of the early portion of practice playing in the slot position, Rogers' usual spot.
Rookie tight end Vance McDonald missed his second straight practice, and Harbaugh said the second-round pick, who led the 49ers in receiving yards against Denver, would not play against Kansas City.
With Patrick Willis (hand) out of action, Michael Wilhoite has filled in well at inside linebacker. Wilhoite still is the main backup there, but good-looking rookie Nick Moody and Nate Stupar also received plenty of snaps with the first-team defense.