The combination was supposed to deliver a championship to Houston.

It hasn't. It won't.

The Rockets asked for and received a disabled player exception - the NBA's version of short-term disability from the salary cap - allowing the team to sign Trevor Ariza, which it did on Wednesday, because Yao is not expected to be able to play next season due to a broken bone in his left foot.

McGrady, recovering from microfracture surgery on his left knee, has one year left on his contract. The Rockets are listening to trade offers and quite likely will move McGrady by next season's trade deadline, which is probably about the time he will be ready to return to action.

Oh, Yao could have surgery on his ailing foot and recover in time to join the team late in the season. And the Rockets might fail to find a suitable trade partner for McGrady. And next spring the two could be high-fiving in the playoffs.

More likely, the next time Yao and McGrady team up will be at an old-timers' game.

Fans have come to grips with losing McGrady. Heck, a host of them are willing to go to his crib and help him move. Fans should now face the more sobering thought that Yao may never again play for the Rockets .

The career-threatening injury isn't the only issue.

The seven-year veteran has just one year left on his contract, with a second option year he'll likely exercise thanks to the injury. One of those two years he will probably sit and watch.

As for the other ??

After rearranging their style of play without Yao this coming season, will the Rockets want to go back to the "gotta get it to Yao" offense they so often struggled to run in two seasons under Rick Adelman?

The Rockets have some tough choices to make.

Is it worth having the oft-injured big man - returning from a year off, mind you - around for a lame-duck season (2010-11) if there are no plans to re-sign him after that?

Too fragile for future

It would make little sense to sign Yao long term when he returns, considering that he missed a season's worth of games in the three-year stretch from 2005-08, had this past season end with the cracked bone in the playoffs and is facing sitting out all of next season.

Basically, the Rockets can no longer consider Yao to be the cornerstone of their championship dreams. He is too fragile.

The Rockets are about to reach a point where they aren't getting enough out of Yao when healthy to make up for what they aren't getting from him when he is injured.

A year from now, what will be the trade value for the league's most talented center, coming off a serious injury?

Will the franchise's dealings with Yao be more about business than Basketball?

Yao has brought worldwide attention to the Rockets , not to mention several lucrative sponsorships with Chinese companies.

But can he bring a championship to Houston?

NBA championships are won by star players. Rarely does a title winner not have a major star lead the way.

The Rockets figured they had two in Yao and McGrady. The odds of winning a championship were in their favor.

It didn't work. Just about the time the Rockets got enough complementary talent around them to do damage, they broke down.

Already planning how to get it done without McGrady, the Rockets must now go about building a champion without Yao.

It's not easy to put together a championship-caliber roster. It's almost impossible to put one together that can contend with Yao and without, which is what the Rockets will be left with if they commit to Yao.

Title to come elsewhere?

There is a recognized rule when it comes to superstar NBA players, especially those with a special locker-room presence: If you have one, you keep him, because at some point in his career he is going to win a championship.

Yao is that type of player. But his body keeps letting him down. Still, history says the odds are he will one day win a championship.

Unfortunately for Rockets fans, when Yao broke his foot in May against the Lakers and the injury got worse instead of better, he moved closer to winning that title somewhere other than Houston.

jerome.solomon@chron.com