All that stands between Jonathan Papelbon and the richest contract in the history of relief pitching is a physical, and Papelbon arrived in Philadelphia on Sunday night in preparation for taking that physical Monday.

Papelbon agreed Friday to a four-year, $50-million contract, sources say, that would make him the Phillies' new closer. But he said Sunday night it wasn't the money that drew him to leave the Red Sox and sign with Philadelphia.

"That (contract) doesn't really play a role," Papelbon told WPVI-TV's Jeff Skversky after arriving at Philadelphia International Airport. "The biggest thing that plays a role is the ability to come here and win."

The 30-year-old righthander has spent his entire career with the Red Sox. And while he admitted Sunday night that it was difficult to leave, "that's the nature of this business," he said. "I'm going to leave behind a lot of friends and a lot of memories, but it's a new chapter in my life."

Papelbon's reported $50-million package, which could grow to more than $60 million if he vests his option for 2016, according to sources, would be the most total dollars for any reliever, and would surpass the $47-million deal signed by B.J. Ryan with Toronto.