The Rays first baseman saw team ophthalmologist Mark Sibley Wednesday night -- after experiencing prolonged discomfort when rubbing his eye -- and was playing with a clear contact lense in his left eye to act as a band aid.
Since the minor condition couldn't get any worse, Pena opted to try to stick it out and play in the Rays' first playoff game with the contact in place.
"Of course I am going to try," Pena said. "But when I was throwing the ball in the infield, I was having a hard time. I had to extra focus to actually catch my throws from my infielders. And I said, 'This is getting more and more dangerous right here' -- not just for me, but for the team."
Pena told Rays head athletic trainer Ron Porterfield of the problem and the first baseman did not resume the field for the third inning, as Rays manager Joe Maddon promptly put utility player Willy Aybar at first.
Maddon said he was already aware of the situation and while Pena looked "OK" during pregame batting practice, he wasn't entirely convinced.
"It's one of those quick-healing things," Maddon said. "But it can present a problem in the initial phase."
Following the game, Pena called the move the "right thing" to do and anticipated having full vision back before Friday night's game, which is slated for 6 p.m. ET.
As for his first-inning strikeout at the hands of Javier Vazquez?
"First, I thought this might be fun [since] I can't really see," Pena said, recanting the story with a laugh. "What about if I get ahold of one right here, even though I'm blind? It didn't really quite work out that well. Of course, I'll still strike out with two good eyes, you know? But it doesn't really make it any easier when you have one bad eye."
Following Thursday's game, Maddon echoed Pena's prognosis and expected the cleanup hitter to be back full-throttle on Friday.
In his second season for the Rays, Pena hit .247 with 31 home runs and 102 RBIs. His 77 home runs over the course of the 2007-2008 seasons are second in the AL to Alex Rodriguez's 89 over that period.
Brittany Ghiroli is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.