Michael Perez/AP
Though Papelbon's has been strong at times - he posted a pretty solid season in 2014 - the contract has largely been a nightmare for the Phillies.
Papelbon's inconsistency, combined with his personality, has ruffled feathers among the Phillies and their fans.
Most recently, in an interview with Boston Globe's Julian Benbow, Papelbon said he doesn't feel like a Phillie despite spending three years with the team:
"The Red Sox are a part of who I am, man. I don't really feel much like a Phillie.
"Boston's where I was born and raised. It's kind of like that, you know. It's the city you were born and raised in."
...
"It's been a tough transition over here. I'm not going to lie. It's been tough. Tough getting used to the way it is here. It's two totally different organizations.
"The way they're ran, the way they're coached, the players that are on them. Two totally different styles of baseball. I don't know if I can honestly tell you if I'm even used to it yet."
After a Wednesday night game in which Papelbon recorded a save, he was asked about his comments in the Boston Globe and said, "I've never been embraced here, from day one."
He continued, "I don't say anything to piss anybody off, piss the fans off, by any means. I'm honest, you know? I'm a Phillie right now. I play for the Phillies, but there's a big part of my heart that lies with the Red Sox, you know what I mean."
Papelbon's remarks are part of a long series of off-the-field brush-ups.
Early last season, Papelbon reportedly had to be separated from trying to fight radio personality Howard Eskin.
In the middle of the 2013 season, Papelbon made highly criticized remarks after the Phillies fell several games below .500, saying, "I definitely didn't come here for this."
On being traded, he said, "No, I would like to stay here. But if I'm going to have to put up with this year after year, then no, I don't want to be here. Why would you? Why would anybody?"
Earlier that season, Papelbon also said the Phillies lacked leadership and couldn't just "flip the switch" whenever they want to.
Since Papelbon joined the Phillies in 2011, they haven't posted a record above .500. That, of course, doesn't solely fall on Papelbon, but his up-and-down play year to year and his perhaps overly honest remarks haven't helped the team or endeared him to fans, either.
The Phillies reportedly tried to trade Papelbon this past offseason, but couldn't complete a deal.