"I think, obviously, with Wade going into his first arbitration year, he's a guy we traded for for a reason -- because we like him and we believe that he's going to help us win games," said Red Sox general manager Ben Cherington. "When we traded for him, our full expectation was that he could be here for a while.
"And so we were either going to try to figure out a one-year number either through a settlement or a hearing or look at some different model or different contract. And I think there was interest from Wade, and he expressed through his agent Tom O'Connell about looking at that."
Miley, who came over in a trade from Arizona on Dec. 12, was appreciative that Boston put faith in him with a multiyear deal.
"I'm just excited to get the commitment and everything, and hopefully everything works out and we're going to win some ballgames," Miley said. "I'm just thrilled to be a part of this Red Sox Nation and be a part of the organization and excited to get it going."
The Red Sox hope Miley becomes a core part of the rotation.
"The best predictor of future durability and performance is past durability and performance," said Cherington. "He's taken the ball consistently. He's been a guy that was relied upon by Arizona. Aside from his durability, we had done a lot of work on Wade prior to the trade, just in terms of what kind of guy he was. We had a lot of confidence in what type of person Wade is before we traded for him.
"While we've gotten to know him a little better since the trade, we felt very comfortable with who we were acquiring even before the trade. So it made these talks relatively easy, because aside from his performance and durability, he's got a reputation as a good person, a good clubhouse guy, a good teammate. So it made it easier to get into this kind of conversation."
Drafted by the D-backs in the supplemental first round of the 2008 First-Year Player Draft, Miley went 8-12 with a 4.34 ERA last year, and he is 38-35 with a 3.79 ERA for his career.
With the agreement, Boston has no remaining arbitration-eligible players.
Miley's contract includes a $500,000 signing bonus. His base salaries are as follows: $3.5 million in 2015, $6 million in '16 and $8.75 million in '17. The club option includes a $500,000 buyout.