The contract will be completed once Colon passes a physical.
Colon, 40, went 18-6 with a 2.65 ERA in 30 starts for the Oakland Athletics last season. He will join Jonathon Niese, Zack Wheeler and Dillon Gee in the rotation, helping to offset the loss of ace Matt Harvey. Harvey is due to miss 2014 recovering from Tommy John surgery.
The deal comes a day after the Mets formally announced the signing of outfielder Curtis Granderson to a four-year, $60 million contract. Although often dinged for their payroll constraints, the Mets already have committed $87.25 million to free-agent contracts this offseason.
"Excellent signing by Mets," one National League scout told ESPNNewYork.com after learning of the Colon deal. "The Mets have had a productive 72 hours."
The Mets' fifth starter could end up being an in-house candidate such as Jenrry Mejia -- or, less likely, a prospect such as Jacob deGrom or Rafael Montero. Or the Mets could go for a low-cost free agent such as re-signing Daisuke Matsuzaka or Aaron Harang.
Either way, it would buy time until the Mets promote top prospect Noah Syndergaard midway through the season. Meanwhile, with their outfield now bolstered with the additions of Granderson and Chris Young, and with the impending Colon signing lessening the sting of losing Harvey for 2014, the Mets now can focus on trying to trade from their surplus at first base.
The Mets have been trying to shop Ike Davis to teams including the Milwaukee Brewers, Tampa Bay Rays and Pittsburgh Pirates. But general manager Sandy Alderson insisted the club is not going to give Davis away just because they also have Lucas Duda at first base.
Davis, who is eligible for arbitration, is expected to earn about $3.8 million in 2014. He is not eligible for free agency until after the 2016 season.
"Let me emphasize one thing: We're not in the business of giving players away," Alderson said. "We don't expect to get in that business."