Peterson kept Jimmy Nelson's tough start from turning into a blow-up on Thursday night with a pair of early-inning defensive gems against the Royals. His diving catch in the second inning and on-target throw to the plate kept the Brewers close in what became a 3-2 loss at Kaufmann Stadium.
"He's got a highlight reel here in three weeks playing defense," manager Craig Counsell said. "I've got about 6-7 plays that are big, big plays."
The reel got longer on Thursday. With a runner aboard in the second inning and the Royals already leading, 3-0, Peterson ranged toward center field to make a spectacular diving catch of Lorenzo Cain's sinking line drive. The catch ended the inning and robbed Cain of extra bases, and likely an RBI.
In the third, Peterson saved a run again with a strong throw home. With two out and Alex Gordon at second base, Peterson scooped-up Salvador Perez's single and fired a strike to catcher Jonathan Lucroy for the inning-ending out. It was Peterson's third assist in nine games in the outfield this season.
The 27-year-old Peterson came to the Brewers after bouncing around the waiver wire -- from the A's to the Cubs to the Brewers -- in the span of four days in December. He began the season at Triple-A Colorado Springs before a promotion to Milwaukee on June 3, and throughout his career has actually been regarded for his bat over his glove.
"I played first base all growing up, so I'm still getting used to the [outfield]," he said. "I would consider myself more an offensive player, but I think that I can hold my own on defense."
Peterson switched off first base after the Cardinals made him their second-round Draft pick in 2008.
"I profiled better as an outfielder," Peterson said. "I never really was much of a home run hitter, and I can run better than I think I get credit for. So playing first base growing up was more that I was left-handed and just kind of got put there."
The Cardinals traded Peterson to the A's in July 2009, as part of the Matt Holliday deal, but Peterson only enjoyed a cup of coffee in the Majors in Oakland -- two games in 2013. Now, he's positioned to play a significant role for the Brewers, who rested center fielder Carlos Gomez again on Thursday because of right hip and leg soreness, and may entertain offers for Gomez and outfielder Gerardo Parra ahead of the non-waiver Trade Deadline.
"That's all I can ask for, is to get to play," Peterson said. "I spent the last couple years in Triple-A and felt like I deserved an opportunity to play in the big leagues, and it's not always there. I'm glad to finally be up here, and not only be here, but actually be getting a chance to play while guys are going through some soreness."
Adam McCalvy is a reporter for MLB.com. Follow him on Twitter @AdamMcCalvy, like him on Facebook and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.