Wilhelmsen was a long time staple in the Mariners bullpen up until the end of 2015. He pitched exceptionally, especially in 2012 and 2014 when his ERA was at or below 2.50.
When he wasn’t coming in as a middle-reliever, Wilhelmsen had the chance to shut down games as the M’s closer (mostly in 2012 and 2013).
Over his four years in the Pacific North-West, he tallied sixty-seven saves; enough to tie him with the M’s mid-nineties closer, Norm Charlton, for the fifth most saves in Mariners history.
At the end of 2015, he was exchanged for the Texas Rangers, Leonys Martin, who is currently the Mariners centerfielder and team spark plug.