SAN DIEGO -- Milwaukee Brewers rookie left-hander Robert Gasser has decided to have Tommy John surgery, which will sideline him for about 12 months.

Gasser's decision came after he received multiple opinions on the best way to treat the left flexor strain that sent him to the injured list June 5.

Gasser, 25, is 2-0 with a 2.57 ERA in five starts -- all wins for the NL Central-leading Brewers -- after missing the end of spring training with bone spurs in his throwing elbow. He last pitched June 1 and reported tightness and soreness the next day.

"Tough break for him, obviously," manager Pat Murphy said before the Brewers opened a four-game series against the San Diego Padres. "The reasoning you can understand, right? Get it taken care of now, back in hopefully 12ish, 13ish months and be able to hopefully contribute.

"I think the one thing he got out of the year was he understands, 'I can pitch in the big leagues. I can be successful.' He had as good a five starts as anybody could hope for in their first five starts in the big leagues. I think that's a big win for the organization and a big win for him. He knows he can do it, the organization knows he can do it, so it bodes well."

Gasser was drafted by the Padres in 2021 and was one of four players sent to Milwaukee for closer Josh Hader on Aug. 1, 2022.

Brandon Woodruff and Wade Miley have already been ruled out for the season.