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 30-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.
SportsNation: Free Agency
How long of a contract would you give Albert Pujols? Who's the best free agent pitcher? Can you name all of baseball's biggest contracts? Vote!
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.
It remains uncertain whether the Phillies will have to surrender their first-round draft pick next June to the Red Sox as compensation for Papelbon, because draft-pick compensation is one of the unresolved issues still on the table during the ongoing labor talks.
Under the current rules, because Papelbon is a Type A free agent, the Red Sox would receive the Phillies' No. 1 pick, the 31st overall pick, in the draft.
However, the players' union has been seeking to reduce the number of premier free agents who would require a team to surrender a draft choice. So until labor negotiations are completed, neither team can be certain of the new definition of players who would still require compensation.
Nevertheless, a source familiar with the labor talks predicted Friday that Papelbon is still likely to be among the elite free agents who would cost their team a No. 1 pick.
The deal 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.
Information from ESPN.com senior writer Jayson Stark was used in this report.
And when someone breaks our wings, we simply continue to fly...
Usually on a broomstick but we're flexible like that