Oswalt has a no-trade clause and is due about $25 million on his contract through 2012. The Cardinals want a significant portion of that money paid by Astros.
Oswalt has spent his entire 10-year career with the Astros, who drafted him in the 23rd round in 1996. Oswalt is 6-11 but has a 3.12 ERA this season. He is a three-time All-Star who has finished in the top five of the NL Cy Young voting five times.
The Astros are buried in fifth place in the NL Central while the Cardinals lead the Reds by just 1 1/2 games. The Phillies are in the third place in the NL East, seven games out, as they try to win their fourth straight division title.