Roy Oswalt, RH Mark Mulder, LH (20-12, 2.94) (16-8, 3.64)
Let's be realistic about this: The only starts the Cardinals have won this series have been Carpenter's, and he's the only guy on the Cardinals that can pitch with Pettitte, Oswalt and Clemens. They lost to Oswalt, they lost to Clemens, and then they lost to Brandon Backe, which was a game they really needed to win. Now they're still on the brink of elimination and need to win twice, against Oswalt and Clemens, to go to the World Series.
On the other hand, they have home field for those two games. If they can push this to a game seven, anything goes. Carpenter would maybe even be available to work out of the bullpen for an inning or two to help with their lame bullpen. They'd certainly have Suppan available for that, as Morris would start.
That said, I like the Astros tonight. Oswalt has pitched well in his two postseason starts thus far (2-0, 2.51, 13 K in 14.1 IP), and I don't think Mulder is good enough to get this done. If it goes to seven, I won't be disappointed, because as I said before, this has really become a hell of a good rivalry the last two postseasons, and I always love a good rivalry.