Per Rotoworld:

The Astros are looking at bringing in free agents Paul Wilson and Pedro Astacio to compete for rotation spots.
Since they traded their fourth starter for someone they want to be a No. 2 in Jason Jennings, the Astros still have two open rotation spots. It'd be nice if they had one more sure thing before dipping into the Wilson-Astacio-Ortiz pool of free agents, but the Carlos Lee signing left them with little flexibility.