The very unique personalities -- there's "Pap" and "Cinco Ocho," an alter-ego created in 2007 -- of the 32-year-old right-hander are easy to dismiss as being childish. But in a game that's often dissected in its every inch, a blank mind isn't necessarily the worst thing.
Paplebon has proved that.
As he sat in the visitors' dugout at Fenway Park on Monday before the Phillies were set to begin a two-game Interleague series that will continue with two more in Philadelphia starting Wednesday, Papelbon didn't seem all that fazed about facing his former club.
"In my role, if I'm out there thinking, I'm going to lose," he said. "I've taken that into my life and I just kind of go. I really don't think about a whole lot of things until maybe it's too late. I just go."
Papelbon has been every bit as good with the Phillies since joining them in 2012 as he was in seven years with the Red Sox. His numbers are almost identical, with a 2.13 ERA in Philadelphia compared to a 2.33 ERA while in Boston.
If he does pitch at Fenway Park this week as a member of the opposition for the first time, he won't be coming out to "I'm Shipping Up to Boston," a song by the Dropkick Murphys, a local band. New Red Sox closer Andrew Bailey borrowed the entrance song after the Boston Marathon bombing.
Papelbon doesn't mind.
"I like it man, I really do," he said. "I think it's for a good cause and it has become a song that's been [nostalgic] for this city when we won in '07. The Dropkicks are a huge thing here in Boston and I think it's cool, man."
Papelbon, who makes up one-third of an elite group of closers to ever play the game, doesn't have much to be worried about. He's already cemented himself in history books.
Only him, Billy Wagner and Mariano Rivera have saved at least 250 games with a career ERA of 2.50 or below. And he's one of just five pitchers to ever save at least 30 games in at least seven straight seasons.
"Health has a lot to do with it," Red Sox manager John Farrell said. "He's a guy that's been able to stay healthy his entire career."
While the Phillies have enjoyed Papelbon's success, the Red Sox have struggled to find their own consistent closer.
Since Papelbon left following the 2011 season, the Red Sox have blown 38 percent of their save chances, going 45-for-78 as nine different pitchers have collected at least one save.
Farrell was asked if there was any regret that the Sox didn't re-sign Papelbon, who eventually found a home with the Phillies at a price of four years and $50 million.
"I don't know that you can say there's regret," Farrell said. "He obviously got a heck of an opportunity and a heck of a deal from Philly. I was talking with someone about this the other day. He closed here for six straight years. I don't know that you're going to see many closers do that in any market, with any team, because that means they came up through the system or converted to closer and held down that job until free agency took them elsewhere. What he did here was very rare -- not to mention the success for the length of time in which he did it."
Papelbon said he has never thought about what it would be like if he was still with the Red Sox, but he expected success for them this season under their new manager, who was Papelbon's pitching coach from 2007-2010.
"I'm not surprised what John has done," Papelbon said. "John is one of the most organized, complete managers I think you'll come across. Nothing catches him off guard, he's always prepared, always has a game plan. When I was with him as a pitching coach, that's just the way he was. I think he'll be a good manager for a long time. I don't think there are many that are on his level."
There aren't many closers on Papelbon's level, either.
As he walked onto the field Monday, he said the only thing he was wondering was if visiting clubhouse manager Joe Cochran "has the Double Bubble that I like."
It's a unique thought process, or lack thereof. But it's proven to be successful.
"He's got a very good short-term memory," Farrell said. "So the days that don't go well, he puts it behind him."