Most closers are happy to have two strikeout pitches, and Wilhelmsen has long been comfortable throwing his wicked curveball, even in full-count situations.
Wilhelmsen struck out the Rays' Hideki Matsui with his changeup on Saturday at St. Petersburg, then teased the Yankees with it a time or two during Tuesday's 4-2 win while notching his 11th save since replacing Brandon League as Seattle's closer in June.
"I'm kind of forcing myself to do that," Wilhelmsen said of the changeup. "I'm going to keep throwing it and wait until I can throw that for a strike whenever I want. I want something else [to throw] to lefties. That's what we're working with right now."
Manager Eric Wedge said the addition of the change has surprised him as well.
"I'd seen him mix it in from time to time, but not in those types of situations," Wedge said. "The Matsui changeup in Tampa, that was the first one that stuck out to me. He's a confident guy. He pitches with confidence and conviction and throws every pitch with that. That's what you're seeing with the changeup. It just adds to his arsenal."