Rob Neyer wrote a counterpoint to Jon Heyman's column (linked earlier) regarding Roy's contract status, and the "difficulty" in trading him:
According to FanGraphs, Oswalt was worth $14 million last season, and is heading toward $18 million this season. That's $16 million per season. Granted, you might not be able to justify those salaries if you're running an American League team, and you might not be able to justify spending that money and giving up two prospects. I'm just saying that Oswalt's contract really isn't outrageous, and that exercising the 2012 option wouldn't be a terrible risk.