Oswalt was selected by the Astros in the 1996 MLB draft. He made his MLB debut with Houston, in 2001, finishing his rookie season with a win–loss record of 14–3. Oswalt was a back-to-back 20-game winner in 2004 and 2005. He helped lead the Astros to their first World Series appearance in 2005, and was named Most Valuable Player of the 2005 National League Championship Series (NLCS). When Oswalt left the Astros in 2010, both his wins (143) and strikeouts totals (1,593) ranked second in franchise history to Joe Niekro (144) and Nolan Ryan (1,866), respectively. Oswalt was a three-time All-Star, selected from 2005 to 2007.