Willis McGahee has already started talks with the Ravens about a contract extension.
Baltimore announced the deal Thursday afternoon.
Buffalo dealt McGahee in anticipation of difficulty with his contract, which has one season remaining at $2.155 million. The Ravens and McGahee have already begun negotiations on a contract extension, McGahee's agent Drew Rosenhaus said.
It's the second year in a row the Ravens pulled off a trade for a marquee veteran. Last year they dealt for Tennessee Titans quarteback Steve McNair, who led the Ravens to the AFC North title.
"This is a runner who can make people miss and has the explosion and speed to take it the distance," Ravens general manager Ozzie Newsome said. "He also has the power and size to run inside. He's a viable receiver out of the backfield and is a good pass blocker, not something every back can do.
"He also plays physical and with toughness, which are things we pride ourselves on here."
The Titans were also reportedly interested in dealing for McGahee.
The Bills, whose remaining running backs are Daimon Shelton and Shaud Williams, are now in the market for multiple backs. They have shown interest in the Colts' Dominic Rhodes and the Titans' Chris Brown, and both have visited the team. Former Patriots running back Corey Dillon has not visited Orchard Park, but the Bills are said to be interested.
Buffalo's first-round pick out of Miami in 2003, McGahee is coming off a down season in which he finished with a career-low 990 yards rushing, but led the team with six rushing touchdowns in 14 starts.
In 2005, he had 1,247 yards rushing and five touchdowns in 15 starts. He established himself as the Bills starter in 2004 with 1,128 yards rushing and 13 touchdowns in 11 starts. That performance led the team to trade former starter Travis Henry to Tennessee the following summer.
McGahee sat out his rookie season recovering from major knee surgery.
The Bills have been disappointed in McGahee for conducting most of his offseason workouts in his native Miami, rather than traveling to the team's Orchard Park headquarters. McGahee also created a stir when he was quoted in a magazine article suggesting the NFL consider moving the Bills to Toronto, a comment he later said was taken out of context.
Source: AP