FORT MYERS, Fla. — Righthander B.J. Hermsen, once a top Twins prospect but who has never climbed above Class AA, will undergo elbow reconstruction surgery and will miss the 2015 season, a Twins official said Wednesday.
Meanwhile, the Twins are still gathering medical opinions about whether another prospect, Australian lefthander Lewis Thorpe, will require a similar season-ending operation.
Hermsen, the Twins' sixth-round pick in 2008 from Manchester, Iowa, will undergo the Tommy John procedure later this month, though it has not yet been scheduled, Twins director of minor league operations Brad Steil said.
Hermsen, 24, was placed on the Twins' 40-man roster two seasons ago after posting a 3.22 ERA in 22 starts for New Britain, but he went 1-10 with a 4.81 ERA for the Rock Cats in 2013 and was removed. Battling injuries in 2014, his ERA ballooned to 7.34 at New Britain and Class A Fort Myers.
He signed a minor-league contract to remain in the Twins organization last winter, but suffered ligament damage while pitching this spring. An examination this week determined that the ligament must be surgically replaced.
Thorpe, 19, threw 10 pitches in a Class A game last Wednesday and was removed after experiencing pain in his elbow. The teenager, considered one of the Twins' top 10 current prospects, suffered a sprained ligament late last season, in which he posted a 3.52 ERA in 16 starts for Class A Cedar Rapids, but he appeared healthy again during a brief appearance in an intrasquad game on March 15, hitting 93 mph with ease.
The Twins have shut Thorpe down for now, as they wait for a medical consensus on what to do next.
