MILWAUKEE -- The Brewers optioned struggling starter Wily Peralta to Triple-A Colorado Springs before Sunday's series finale against the Mets at Miller Park. Matt Garza will be activated from the 60-day DL and start on Tuesday in San Francisco, manager Craig Counsell announced.
Peralta's 6.68 ERA through 13 starts ranks last among all qualified Major League starting pitchers. The Brewers' Opening Day starter, Peralta struggled to put together a string of consistent outings, only completing six innings in two of his starts.
"We were just a point where we have six starters, and we need to get better performance out of that spot," Counsell said. "So that's really what it came down to in the end. We're looking for a little better performance from that spot, and so that's what we're going to try for the time being."
Garza suffered a right lat strain during an exhibition game in his final start of Spring Training. He made three rehab starts for Class A Wisconsin, throwing 74 pitches in his final start on Thursday, allowing three runs over five innings.
Garza signed a four-year, $50 million deal prior to the 2014 season and has produced mixed results in his two years with Milwaukee. He posted a 3.64 ERA in 27 starts in '14, but '15 was a different story. Garza publicly disagreed with his removal from the starting rotation in September following 25 starts in which he held a 5.83 ERA and 1.59 WHIP.
Peralta's demotion came less than 24 hours after hitting his first career home run and giving up three runs over five innings in Saturday's 7-4 win. He was informed of the decision Sunday morning and left the clubhouse prior to the start of the game.

"Obviously, any time a player's been in the Major Leagues and had some level of success that Wily has had, it's a tough conversation," Counsell said.
Peralta had fallen from his 2014 form, when the Brewers' former top prospect broke out with 17 wins and a 3.53 ERA. His command and strikeout numbers have diminished since, and with one Minor League option remaining, the Brewers opted for him to work through his struggles in Triple-A.
"He's talented enough to succeed at this level," Counsell said. "We're just not getting the performance we need. We're looking at ways to match up the talent with performance."
In the high-altitude environment of Colorado Springs that can prove tough on pitchers, the Brewers will have to evaluate Peralta's performance despite possibly inflated numbers.
"The thing you have to distinguish from is how he performs and what the numbers look like," Counsell said. "That's what we have to evaluate differently. So if you guys just look at it here, you're not getting the whole story. We're able to get a little more of the story as to how he's actually pitching and what is getting better and what we're working on. That's the next level of analysis for us."
Jimmy Nelson's start, previously scheduled for Tuesday, will be moved back to Wednesday with the activation of Garza.