ATLANTA -- Before Tom Glavine could even sit at his locker late Friday afternoon, he was stopped by John Smoltz. If the evening's game was postponed due to rain, Smoltz wanted to know if Glavine would switch rotation spots with him and pitch in Monday night's series opener at chilly Coors Field.

Once rain postponed Friday's game, Glavine accepted this proposal and cancelled his assignment to face his former Mets teammates this weekend.

For Smoltz, this means he'll make his season debut on Sunday afternoon against Mets ace Johan Santana, who won't provide the same kind of long-term problems that Smoltz's right shoulder could experience in the winter-like conditions that await the Braves in Denver this week.

"I'm not afraid of any situation," Smoltz said. "It's just that I've got to do what's best, and what's best for me is what's going to be best for the team. If this were July, it wouldn't even be an issue."

After Friday's postponement, Braves manager Bobby Cox said that he was just going to push his entire rotation ahead one day. But on Saturday afternoon, he announced that he was flip-flopping Smoltz and Glavine in the rotation.

"It wouldn't be fair for Smoltzie in his first start to be out there under all of these circumstances," Cox said. "It's the smart thing to do."

On a number of fronts, this slight alteration made plenty of sense. Along with Smoltz not having to subject his shoulder to the tightness that the cold temperatures could cause, Glavine doesn't have to feel the intense pressure that would have been present if he'd have started against Santana and the Mets on Sunday.

"It gives me a chance to get my feet on the ground," said Glavine, who returned to Atlanta after spending the past five seasons with the Mets.

Over the past 10 days, Smoltz hasn't felt any of the tightness that was apparent in between his neck and right shoulder during the side session he threw on March 15.

But along with concerns about subjecting his shoulder to cold weather, Smoltz's desire to make this switch came with knowledge that it typically takes a pitcher longer to recover after pitching in Denver's Rocky Mountain thin air.

Smoltz substituted his first three scheduled Grapefruit League starts with three simulated games. His only true game against Major Leaguers in March came on March 15, when he pitched into the fifth inning against the Rays. Thus, it might not have been wise for him to test his endurance during his first start in that setting.

"It's always a little harder to recover out there," Glavine said. "There's potential for him to kind of set him back a little bit. So if we can avoid that, I don't have a problem with that. It's not the best place to pitch. But long-term or long haul, if it's better for John and us, then I don't care."