All-star center Yao Ming said yesterday that he's still not sure what to expect from himself this season after foot surgery in July 2009 sidelined him all of last year.

"After one year away, I keep telling myself, 'Be patient, be patient,'" Yao said, the day before the Houston Rockets open training camp. "This injury cannot be helped by one day. Last night, I was thinking, 'This season is about to start.' It's time to go."

Yao was cleared by team doctor Tom Clanton to resume basketball activities a month ago. His reconstructed left foot has held up fine in individual workouts and scrimmages, but the true tests will come when the Rockets start playing exhibition games. Houston opens its preseason against Orlando on Oct. 5.

"I haven't played in a real game yet," Yao said. "I don't know how it might react to the intensity. Hopefully, we can learn as soon as possible."

Coach Rick Adelman and general manager Daryl Morey are as eager as anyone to find out. Following doctors' orders, the Rockets will limit Yao to 24 minutes per game, and it's up to Adelman to decide how those minutes are divided.

In the meantime, Adelmam said it's up to Yao to build his conditioning to the point where he can even endure 24 minutes.

"Yao is the big unknown," Adelman said. "I don't think it's fair to say he's going to play 24 minutes. It's got to be something that he feels comfortable with, and it's going to benefit our team, in the long run. It's something we just have to gauge."

Morey says the 24 minutes are a "hard number" for now, but added that the Rockets will confer with doctors throughout the season to see if Yao might be able to play more.

"As he progresses and as the doctors get more info, we may get new guidance on how he may be used," Morey said. "Right now, it's something we'll sort of take day-to-day, what's best for the team, what's best for Yao Ming?

"Our constant focus is, we need him to help us win the regular season, more importantly, we need him to help us win in the playoffs if we can get there," Morey said. "Also, for his career, we're obviously taking a cautious approach."

The Rockets went 42-40 and missed the playoffs with Yao on the sidelines last season. Chuck Hayes, at 6-foot-6, played center, and Houston relied on an up-tempo offensive style to win games.

Adelman said the main directive in training camp is to improve defensively, and the players know it'll help to have their 7-foot-6 center back patrolling the lane, even in limited action.

"It's going to take a while for the big fella to get in shape and get back into the flow of things," forward Shane Battier said. "But he'll get there eventually, and when he does, he's going to really help us."

Point guard Aaron Brooks, who averaged 19.6 points last season, said Yao's presence will open opportunities for the perimeter players on the offensive end, as well.

"From the time he gets on the floor, he'll definitely be a focal point," Brooks said. "We had a couple of games last year, where we went about five minutes without scoring a basket. We need him, he's going to help us. I'm just looking forward to playing with him again. I've played a couple of pickup games, and I'd forgotten how easy it was to play with the guy."

Yao has averaged 19.1 points and 9.3 rebounds in seven seasons since the Rockets drafted him with the No. 1 overall pick in 2002. He turned 30 on Sept. 12, and says he's fought the urge to push himself too hard as he tries to regain his old form.

Yao missed at least 25 games with injuries in three straight seasons between 2005-08, and ranks this ongoing recovery as the most challenging of his career. "Some of the days, I'm out of patience, I just want to do something," he said. "I would like to push myself a little bit faster, but in that situation, overdoing it will slow you down. You have to really manage yourself mentally, and keep yourself in a very good attitude. I'm not used to that."