Yet Nolan relishes that prospect, particularly after watching several impressive performances in the 49ers' 26-21 exhibition win over the Oakland Raiders on Saturday night.

During the coach's first two camps in San Francisco, he often chose the lesser of two evils — and the talent-poor Niners won 11 games in two seasons. This fall, he's picking from a position of strength, everywhere from right tackle to backup safety.

"I like the competition that's going on," Nolan said Sunday. "It inspires a lot of guys to keep going and play hard. I'm an advocate of the four preseason games for a good reason. I know from experience, I go back and forth on a number of players. You go from shorts to pads in training camp, and then you go into games, and it's kind of like evaluating for the draft."

Nolan's evaluations mostly have been positive so far, but he still hasn't made up his mind on several spots.

Perhaps the fiercest competitions are on the right side of the offensive line, where first-round pick Joe Staley and David Baas are making bids to unseat starters Kwame Harris and Justin Smiley, who both were the subject of trade rumors in the offseason.

"The rookie is stepping up and competing, so that (competition at right tackle) is probably a little closer than at the right guard," Nolan said. "The biggest thing is I'm pleased we have depth."

Nolan again praised Staley, saying the 28th overall pick from Central Michigan could start the 49ers' final exhibition in two weeks. Harris is a longtime San Francisco scapegoat for his inconsistent play, and Staley — a left tackle in college last season — could move ahead of the veteran despite breaking his right thumb in practice two weeks ago.

"I have high expectations for myself, and I want to prove what I can do," Staley said. "I love to play fast and play physical, and we've been doing a lot of that."

Nolan said Smiley has stepped up his play in the face of a challenge from Baas, the 33rd overall pick in 2005 who has yet to earn a consistent role with the 49ers. Baas was on the verge of being a huge disappointment for San Francisco until his strong play in camp and the preseason.

"It's good that we have a lot of competition on our team, because it makes everybody better," said Baas, who played left guard and center in college at Michigan. "I think either one of us could be the starter, and that's really good in terms of our depth. Whatever chance I get, I just want to play hard."

Nolan was mostly pleased with his backups on the defensive line, who filled in while all three of his projected starters sat out against the Raiders. Defensive end Marques Douglas missed the game because his wife, Sparkle, gave birth to their second child around kickoff time.

Nolan said nose tackle Isaac Sopoaga played his best game in Nolan's tenure, while rookie end Ray McDonald showed a remarkable knack for being quick off the snap. The 49ers were painfully thin at defensive line in Nolan's first two seasons, but Sopoaga and McDonald should fill holes behind starters Douglas, Bryant Young and Aubrayo Franklin.

Taylor Jacobs, who barely played against the Raiders after his wife gave birth on Friday, also received another round of praise, with Nolan calling him the 49ers' No. 3 receiver. The veteran caught just four passes last season after arriving in a training-camp trade with Washington, but has wowed San Francisco's coaches in training camp.

The 49ers also have ample depth behind Jacobs and starters Darrell Jackson and Arnaz Battle — another remarkable development for a club with one of the NFL's worst receiving corps in each of the past four seasons.

"I'd like to keep six (receivers) if there's six that warrant being on the team," Nolan said.