Jonathan Papelbon is closing the book on his tenure with the Boston Red Sox.
Papelbon, the longtime Red Sox right-hander who has anchored their bullpen for six years, including a World Series title in 2007, has agreed to a four-year, $50 million deal with the Philadelphia Phillies pending a physical, a source familiar with the negotiations told ESPN.com senior writer Jayson Stark on Friday.
The deal includes a vesting option that could take it beyond $60 million for the 31-year-old, the source said.
If finalized, the contract would be the largest total package ever signed by a relief pitcher. The previous high was the five-year, $47 million deal signed by B.J. Ryan with Toronto in December 2005.
The $12.5 million average annual value of the deal would be tied for the second-highest ever signed by a reliever.
Mariano Rivera's $15 million a year, in each of his last two contracts, ranks No. 1.
Papelbon's annual pay would be tied with former Phillies closer Brad Lidge, who signed a three-year, $37.5 million extension during the 2008 season, covering the 2009-11 seasons.
Papelbon takes 219 career saves, with a 2.33 ERA and 1.02 WHIP, with him to Philadelphia, despite pitching his entire career in the AL East.
Papelbon was a Type A free agent, and no Type A free agent had changed teams this winter as the compensation rules governing premier free agents continue to be negotiated by players and owners at the bargaining table.
The deal also comes after the Red Sox said they would like to re-sign Papelbon, and the Toronto Blue Jays and Florida Marlins reportedly also had expressed strong interest.