Pena has 303 walks, while McGriff drew 305 during his Rays career from 1998-2001 and in '04.
Pena, who tied for the American League lead in home runs in '09, values his walks.
"If I'm walking, I'm hitting," Pena said. "[Rays manager] Joe [Maddon] says that, and I'm agreeing with him 100 percent of the time. And if you think about it, a walk is just as good as a hit. You're on first. You heard that, right? That's a very popular line. It's true. ... You're on first base, and you're helping your team out."
While Pena values his walks, he said a hitter can't go up to the plate trying to draw a base on balls.
"I've seen times where I'll have walks and I'm happy I'm on first base, but I know that earlier in that count, I missed two pitches I could have hit for a double, maybe a home run, or I've just flat taken a pitch down the middle," he said. "So I know you cannot go up to the plate trying to walk, or trying to work counts."
Pena described his "perfect world" scenario for getting a walk.
"You have a plan," Pena said. "You're waiting for a good pitch to hit. You don't get it, you go to first. That's the way I like to get them."
While Pena likes to walk, he wouldn't go so far as to say that drawing a walk was more satisfying than hitting a home run.
"But sometimes I'll get a walk and I'll be like, 'That's an outstanding job, good job,'" Pena said. "And I go to first base and I'm like, 'Great job, I feel happy about what I just accomplished. The guy was throwing some tough pitches and I laid off them.' Maybe I watched him on video and I kind of knew, so there is some pride to be taken there, but it definitely feels better to crush a baseball."
Only three other Major Leaguers besides Pena have 300 or more walks since the start of 2007: Adam Dunn, Albert Pujols and Jack Cust.