Travis Hafner and the New York Yankees have agreed to a $2 million, one-year contract that allows him to earn up to $4 million more in bonuses based on plate appearances.Limited by injuries the past five seasons, the 35-year-old gives the Yankees a designated hitter with power potential from the left side of the plate. He essentially takes over the role filled last season by Raul Ibanez, who signed a $2.75 million, one-year deal with Seattle in December.Hafner played in only 66 games for Cleveland last year because of knee and back problems and hit .228 with 12 homers and 34 RBIs in 263 at-bats. The Indians declined a $13 million option, electing to pay him a $2.75 million buyout.The Yankees' projected 2013 payroll is about $208 million for 18 players.Platoon for Nap?The Boston Red Sox have signed first baseman Lyle Overbay to a minor league contract, an official with knowledge of the deal told The Associated Press.If he makes the Boston roster out of spring training, Overbay would share duties with former Rangers catcher/first baseman Mike Napoli.Overbay is a career .270 hitter with 133 homers and 581 RBIs in a 12-year career with the Blue Jays, Braves, Brewers, Diamondbacks and Pirates.Hart to rehabBrewers first baseman Corey Hart said via text message his knee surgery went so well he's already begun rehabilitation.Hart said he's going to have an MRI in three weeks and if all is well it's "realistic" he could be ready to play by the end of April, nearly a month ahead of what was projected.Briefly Mets: New York agreed to a minor league contract with outfielder and former Ranger Marlon Byrd, who was suspended 50 games last season for testing positive for a performance-enhancing drug. Reds: Left-hander Manny Parra signed a one-year, $1 million contract. Cardinals: Left-hander Marc Rzepczynski signed a one-year, $1.1 million contract.