LOS ANGELES — John David Booty saw it up close. Though Pete Carroll's office was a couple of hundred yards away, he had to watch on the Internet thanks to the nuances of NCAA rules.

With no fanfare, Joe McKnight started putting his imprint on the USC football program this summer. Because it came in player-only, unofficial workouts, Carroll's only glimpse was via the World Wide Web.

Booty, the Trojans' Heisman Trophy-hopeful quarterback, liked what he saw from McKnight. He dropped some serious names while trying to describe him.

"It's almost like he has the speed of Reggie (Bush), but the hands of Steve Smith, if you believe that," Booty said. "It is kind of like that in a way. It's really special."

For a team that otherwise has it all — an experienced, fast defense; a returning quarterback; a deep pool of tailbacks — McKnight might be the missing ingredient. He looks like a playmaker, someone who can turn a short gain into a 70-yard touchdown.

USC, which lost its two most explosive offensive players, might have an opening for a home-run hitter. The Trojans start practicing this week, and taking a closer look at McKnight will be part of the coaches' agenda.

Ranked No. 1 in virtually every publication that produces a poll, USC will begin blending McKnight and the rest of another ballyhooed recruiting class into a deep mix of veterans. It's still too early to know which of them will contribute right away, but Carroll, as usual, is keeping an open mind.

"That's why Joe came here," Carroll said. "He looked at what Reggie did and then looked at the new guys who came in last year and saw that none of the guys took that spot."

If not for the lack of a big hitter, this USC offense would be almost as formidable as the defense. Booty parlayed a strong finish in the Rose Bowl into a near-perfect set of spring practices. He spent this summer working out and says he put on about 12 pounds, which means he weighs about 220.

A year ago, he was five months removed from surgery to repair a herniated disk in his back.

"I second-guessed my body last year. I didn't know how it'd be when I got hit or what would happen. It held up," Booty said. "Now I know it's going to hold up, and now I've built it up. I feel 200 times better than I did last year."

The Trojans also have a returning All-American at left tackle, Sam Baker. They even have a ready replacement for Dwayne Jarrett. Patrick Turner might be even a bit more physically imposing than the lanky Jarrett.

But the lack of depth and flash at receiver is vexing. Jarrett and Smith accounted for 2,098 receiving yards between them, about 61 percent of USC's total. They caught 21 touchdowns out of USC's 30 by air.

Somebody is going to have to step into the vacuum, and, as usual, the Trojans recruited to fill the void. Turner and sophomores Vidal Hazelton and Travon Patterson will get the first opportunities, but younger players will also get a chance to help.

USC coaches talked Ronald Johnson out of Michigan, and David Ausberry, the team's biggest receiver, takes off his redshirt.

"I'm not lacking confidence in this receiving group or any other aspect of this offense," Carroll said. "I think we can do anything we want to."

But Carroll reserves his heartiest praise for a defense that, especially early, will be the strength of the team. Linebacker Dallas Sartz is the only graduating starter. Booty freely admits that the defense is ahead of the offense at this stage, but he said it probably was all of last year, too.

Is this the year the offense catches up again?