Pena, a catcher, has played some third, first and outfield in the Minors and winter ball, and he appeared in one game at third for the Atlanta Braves.
"I like to move around a little bit because you never know what's going to happen," Pena said. "I've been doing that ever since I was with the Braves in the big leagues, and I'm very confident out there at third base or at first."
Rookie Mike Moustakas is entrenched at third base, and with both Wilson Betemit and Mike Aviles having been traded away, the only spare infielder left is Chris Getz, normally a second baseman and Yost's other bench option, with Maier and Pena.
"I'm not as good as Moose, but in an emergency, he can trust me in there," Pena said. "I'm not a Gold Glove, but I can stop and throw."
Maier, an outfielder, began in the Minors as a catcher but was switched to third base in his second year, 2004, in the Midwest League. In his pro career, he's played every position except shortstop.
"I played second base in one game at the All-Star Game in Cedar Rapids -- that's the only game at second I've played," Maier said. "Howie Kendrick was supposed to start and he got hurt, and they switched it around somehow and I was the one that got drawn out of the hat to play second."
Which of the two would Yost pick to play third base if necessary?
"Pena ain't that bad over there," Yost said. "I think I'd probably put Brayan over there first."