David Aardsma 2010: Seattle Mariners Closer

David Aardsma will be the Seattle Mariners closer in 2010. In 2009, he moved into the closer role and was very successful, saving 38 games and putting up a 2.52 earned run average. However, if you look a little more closely, there's definitely some risk here. Aardsma 4.29 batters per nine innings. That's already pretty marginal, without considering that at 28 years old, it's the best control he's ever shown in the major leagues. Then consider that his groundball rate was an atrocious 25.3%, and has always been pretty weak. Aardsma certainly has the potential and the strikeout rate needed to succeed as a closer, but if his walk rate rises to it's previous levels, there's a distinct possibility that one of the Mariners other relievers (hopefully Brandon League) will have the opportunity to close at some point this season.