But when Boise Hawks manager Mark Johnson called on him to start the biggest game of the season, he was more than up to the task.
Pena scattered five hits over seven scoreless innings Wednesday as the short-season Hawks beat the Yakima Bears, 3-2, to advance to the Northwest League Championship Series.
Pena (1-0), who struck out two and did not walk a batter, turned over the shutout to the bullpen in the eighth.
"[Pena's] had probably three in a row like this, but he turned it up another notch tonight. It was really fun to watch," Boise manager Mark Johnson said. "He got first-pitch strikes on 90 percent of the hitters, 10 or 12 ground-ball outs and three of the five hits were infield singles."
Brian Smith allowed two runs -- one earned -- while retiring one batter and Eduardo Orozco struck out two over the final 1 2/3 innings to secure the save.
Pena, a 21-year-old native of the Dominican Republic, has traveled between the bullpen and the rotation in recent years. He was 1-4 in 14 games, including six starts, in the Dominican Summer League in his first year as a pro in 2009, then worked as a starter, middle reliever and a closer for the Cubs' DSL affiliate in 2010.
Last year, Pena made 17 relief appearances in the Rookie-level Arizona League. This season, he returned to the AZL and made six appearances out of the bullpen before his promotion to Boise, where he started six games and came on in relief in nine more.
"We just jumped out to an early lead and we had an unbelievable outing from Felix Pena, who threw the ball extremely well for seven innings," Johnson said. "The offense put up three runs, and that was all we needed."
On Wednesday, Cubs' No. 14 prospect Dan Vogelbach came through with the biggest hit in support of Pena.
Hitless in six at-bats in the first two games of the best-of-3 semifinal, the DH delivered a bases-loaded, two-run single in the third inning. It broke a scoreless tie and gave the visitors a lead they never relinquished.
"It was a fly ball that the outfielder lost in the twilight. Two runs scored on that play, and that was huge," Johnson said.
Yakima plated two runs in the eighth to get within 3-2, but second baseman Gioskar Amaya -- whose throwing error on an attempted forceout earlier in the inning allowed a run to score -- preserved the lead by making a diving stop before throwing out Jacob House from his knees.
"He made an error the play before and almost cost us two or three runs. He was really down on himself, then he made that diving play up the middle," Johnson said. "And luckily, it was a slow runner with a bad hamstring. It was another lucky break."
Seeking their seventh title and first since 2004, the Hawks will face Vancouver in the best-of-3 Championship Series. The Canadians host Game 1 on Thursday before the series shifts to Boise for the final two contests, if necessary.
"This is a very young team. This is a great time in their careers, to be in a position like this, to win a championship," Johnson said. "Whatever happens, it's great experience. Some people go through their whole career without a chance to win a championship. To have a chance to win one is a feat in itself."
Vancouver, which swept its semifinal against Everett, split the 10-game regular-season series with Boise.
Wednesday's game marked the end of the Bears' tenure in Yakima. The team will relocate to Hillsboro, Ore., for the 2013 season but will keep its affiliation with the Diamondbacks.