ST. LOUIS -- When seven-time Cy Young Award winner Roger Clemens takes the mound Saturday afternoon for Game 3 of the National League Championship Series, there is a chance the baseball world will be witnessing the final performance of The Rocket's career.

Clemens hasn't said one way or the other if he will return next season, but the 43-year-old would not make another start after Saturday unless the best-of-seven NLCS goes the distance back to Game 7 at Busch Stadium. But if the Astros were to win the NLCS before Game 7, Clemens would start in the World Series.

Of course, there's always the possibility the Astros could be eliminated from the playoffs before then. If that happens, Saturday could be it for The Rocket.

"I haven't thought about that," Clemens said. "2003 is when I really thought about it, to be honest with you. Those final pitches were the hardest for me at that point, because I didn't obviously know what was in front of me, lying ahead. And for that matter, I still don't.

"You know things have changed for me over the last couple of weeks. There's a big part of my heart that's missing now with my mother gone. That's just the way it is. I knew I pitched for her, but I didn't realize how much that I did. But make no mistake about it, that still doesn't diminish -- some of my will is gone but not all of it. You just look at things different."

In any case, it won't be an easy assignment for the future Hall of Famer as the Cardinals, after splitting the first two games with Houston at Busch Stadium, will send right-hander Matt Morris to the mound for the 4 p.m. ET game.

"We all look at [Clemens] and marvel," Morris said. "You know, I get a good opportunity tomorrow to go out and compete with him, so I'm looking forward to it."

Morris is 2-5 with a 3.97 ERA in 14 career postseason games, including 10 starts. But the Cardinals have won three of his last four playoff starts, including two over Houston in the 2004 NLCS.

"Whenever you go up against these guys you're in a battle," Houston closer Brad Lidge said. "They keep throwing aces at us and we throw aces at them. They have one of the best offenses in baseball, they're a great defensive team, but we've really been scoring more runs lately and we've played well at home. It should be another battle."

Typically, when these two teams tangle, a tense game ensues.

The Cardinals won 11 of 16 regular-season games against Houston in 2005. Counting the playoffs, the Cardinals have lost three of the last four meetings to the Astros at Busch Stadium, but all were by three runs or fewer.

Morris beat Houston, 8-5, on April 24, but lost to the Astros the only other time he faced them on Sept. 27. He pitched well, however, allowing two runs on five hits in six innings in a 3-1 loss in the latter game.

In last year's NLCS, Morris had no record with a 5.40 ERA.

"He's always been tough against us," Houston shortstop Adam Everett said. "He's especially tough on right-handed hitters and doesn't give you much to hit."

Clemens, 4-1 with a 2.51 ERA in nine career regular-season games against the Cardinals, was 1-1 with a 2.63 ERA against them in 2005. The right-hander was 1-1 with a 4.15 ERA in the 2004 NLCS vs. the Cardinals.

On Sunday, Clemens pitched in relief for the first time since 1984, pitching three scoreless innings to get the win as the Astros beat Atlanta in 18 innings to clinch the NLDS. Saturday's start will be Clemens' first appearance since then.

"He's rested and ready to go," Astros manager Phil Garner said.