"We were going to call him up [when the Triple-A season ended]. The last couple of days in the bullpen probably just sped it up a little bit," manager Craig Counsell said. "This is the time of the year where you've got the ability to get a guy here when you need it. We've been using guys in the bullpen, which in this case is a good thing, because we've been pitching our guys a lot in big situations because we've been winning games."
Pena is the third of the three prospects acquired in a July 2012 trade with the Angels for Zack Greinke to make it to the Majors with Milwaukee. He follows Jean Segura, who is in his third full season as Milwaukee's starting shortstop, and pitcher Johnny Hellweg, who made eight Brewers appearances in 2013, but underwent Tommy John surgery in 2014.
The 26-year-old, Dominican-born Pena nearly made the Brewers' bullpen out of Spring Training before an assignment to Colorado Springs, where he posted a 4.46 ERA in 43 games, including seven starts. He'd found success recently after a move to the starting rotation, with a 2.37 ERA and a .203 batting average against over his last 30 1/3 innings.
"He's had an interesting season," Counsell said. "He was in the conversation for a long time in Spring Training, and the plan was to transition him to the bullpen. It was mixed results. A lot of his struggles were in Colorado Springs [where the conditions severely favor hitters]. He's always been interesting and on the radar, and he's taken another little step forward."
That's reflected, Counsell said, in Pena's improved walk rate. His 3.5 walks per nine innings were Pena's fewest since 2009 in rookie ball.
"I'm throwing more strikes now," said Pena, who works off a power fastball. "Trying to attack the strike zone."
Asked whether he would like to see Pena start a Major League game, Counsell said, "We'll see how it goes. Innings are what's important."
The Brewers' bullpen should get another infusion on Monday, the day right-hander Tyler Cravy is tentatively scheduled to be activated from the disabled list. He has been sidelined by a right elbow injury, but threw a second bullpen session on Friday afternoon with no trouble.
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.