Given the Angels rotation problems, I would love to see them go after Penny. According to Fangraphs, his FIP is only 4.48, which indicates that his ERA is bloated by playing half his games at Fenway in front of a defense that has been one of the worst in the AL.
It's no secret that the rotation has struggled. While Penny wouldn't be an upgrade over the Angels' top two starters (Lackey and Weaver), he would be insurance in case Santana can't stay on track, and despite his promising start yesterday, it's unclear what the Angels will get from Saunders the rest of the way.
What IS clear is the he would be a significant upgrade over the myriad minor league callups that have been serving as the Angels' fifth starter since the first week of the season. And once the playoffs roll around, he might be useful in a long role out of the bullpen (if he proves to be pitching better than Matt Palmer, who has zero experience in the postseason).
In short, he gives the Angels options, and his underlying numbers suggest that he can still help out a major league rotation. He's cheap, he's a short-term investment, and he can help save the bullpen some wear and tear down the stretch. Your move, Reagins.