Milwaukee Brewers first-round pick Eric Arnett underwent reconstructive surgery on the ACL in his right knee Thursday and is expected to be sidelined for five to six months.
The Brewers made the expectation of Arnett's ACL diagnosis public Tuesday and said the right-hander was scheduled to be evaluated by team physician Dr. William Raasch in Phoenix on Wednesday to confirm whether surgery was needed.
Raasch's exam confirmed initial signs of a tear and he performed Arnett's surgery Thursday morning.
Arnett, 25, told the team he suffered the injury doing shuttle runs while preparing for spring training.
Taken 26th overall in the 2009 draft out of Indiana University, Arnett has not lived up to expectations. The 6-foot-5 right-hander struggled as a starter, posting a 1-13 record with a 6.29 ERA in 25 games over the course of two seasons for Single-A Wisconsin.
The Brewers moved Arnett to the bullpen prior to last season and the move appeared to have jump-started his career. Arnett made 33 relief appearances for Single-A Advanced Brevard County and had a 3.56 ERA in 60 2/3 innings.
Arnett was expected to start the season with Double-A Huntsville, but the torn ACL will likely end his season and hurt the momentum he built in 2012.