FORT MYERS, Fla. -- The Twins optioned reliever Michael Tonkin to Triple-A Rochester after he gave up a run on two hits against the Pirates on Friday.
Tonkin, 25, made four Grapefruit League appearances, giving up three runs on five hits and a walk over four innings. He also tossed two scoreless innings against the University of Minnesota on March 4.
Tonkin had a 4.74 ERA in 19 innings with the Twins last year, while also posting a 2.80 ERA and 10 saves in 39 appearances with Rochester. Twins manager Paul Molitor said the key for Tonkin will be to develop his slider to go with his mid-90s fastball.
"He's been a part of this team in various stages over the last few years and has done some good things, but he needs to become more efficient with his secondary pitches," Molitor said. "It seems to me he gets into trouble because people are looking for that fastball pretty much. They're going to get one at some point, so that secondary pitch has to get better to not just get ahead but to finish. He's got enough life on his fastball, but it gets a little predictable at times."
Rhett Bollinger is a reporter for MLB.com. Read his blog, Bollinger Beat, and follow him on Twitter @RhettBollinger. This story was not subject to the approval of Major League Baseball or its clubs.