Gasser will have surgery Monday to repair UCL damage in his left elbow, Todd Rosiak of the Milwaukee Journal Sentinel reports.
It's unclear whether Gasser is undergoing Tommy John surgery or the internal brace procedure, but he will be out for at least the next 12 months. It's tough timing for the promising young pitcher, as he had pitched well across his first five big-league starts, maintaining a 2.57 ERA and 1.04 WHIP in 28 innings.