A+ For Aardsma

Unless you’ve watched Seattle play quite a bit this year, odds are you don’t realize that David Aardsma has the highest WPA of any relief pitcher in the American League this season. Yes, David Aardsma – the guy who the Red Sox traded to the Mariners for the immortal Fabian Williamson over the winter.

Aardsma’s always been a guy with a big fastball and no command, as his career 5.56 BB/9 shows. He’s on his fifth organization in six years, as everyone has had him previously got tired of seeing him walk the world and decided to go another direction. He’s still walking everyone in sight as a Mariner, but he’s turned up the strikeouts and stopped giving up home runs, so the overall package has worked for him this year, delivering a 1.62 ERA while pitching in extremely high leverage situations.

This kind of breakout year has inspired a couple of people to ask me what Aardsma’s doing differently this year. I’ve told them the same thing – nothing obvious. He’s the same guy he’s always been, with the same skillset as always. He just was better than people realized.

For example, here are his 2009 numbers to date.

33 1/3 IP, 19 H, 20 BB, 41 K, 1 HR, 2.79 FIP, 1.62 ERA

And here’s his numbers last year through July 18th, when he was placed on the DL.

39 1/3 IP, 29 H, 26 BB, 41 K, 1 HR, 3.58 FIP, 2.75 ERA

Not a huge difference, honestly. The strikeouts are up a little bit, but not that much. The hits are down, but that’s what happens when you take an extreme flyball guy out of Fenway and put him in Safeco with some terrific defensive outfielders behind him. Overall, the core performance isn’t that much different from what he was last year before he got hurt. He tried to return in August, but he was a walking disaster – 9 1/3 IP, 20 H, 9 BB, 8 K, 3 HR, 9.52 FIP, 17.36 ERA

Trying to pitch while hurt didn’t do him any favors, ruining his 2008 season line and giving the impression that he was still unable to get major league hitters out. However, before landing on the DL, he was doing just fine. The command was bad, but the strikeouts and lack of home runs made it work. Just like now.

I’m not saying Aardsma is going to continue to post a 1.62 ERA all season. With as many fly balls as he gives up, he’s going to surrender a few more home runs along the way. But Aardsma’s a quality relief pitcher, and we shouldn’t be that surprised that he’s performing well for the Mariners. He did this last year too, but no one noticed.