When reached on his cell phone on Monday evening, Bellhorn confirmed the move to MLB.com. A Yankees official also confirmed the move on the condition of anonymity.
Several published reports had indicated that Bellhorn would sign with the Oakland A's, but he decided in the end to remain in the American League East, as he knows some players and coaches on the Yankees.
"The Yankees seemed interested," said Bellhorn, speaking from the airport in Phoenix, on his way to Seattle, where he will sign a contract on Tuesday. "The Yankees are one of the most well-known franchises in all of sports. Not everybody gets to play for them."
Bellhorn will likely fill the role of a utility infielder, which will probably result in Felix Escalona heading back to the Minors until rosters expand on Thursday.
"I'll do whatever they need me to do," Bellhorn said. "I can play a lot of positions, I can pinch-run, pinch-hit -- whatever they need from me."
Bellhorn spoke recently with Yankees reliever Alan Embree, who signed with the Yankees on July 30 after being released by the Red Sox.
"He just asked me a few questions about how I liked it here," Embree said. "He didn't know what was going to materialize from it, but I told him I enjoy it. I put in my two cents."
Embree believes that Bellhorn will help the Yankees with his glove and his experience.
"He's a great defensive player who will fit well in this clubhouse," Embree said. "He doesn't say much, but he plays great defense and he's been through the battles."
Bellhorn was designated for assignment by the Red Sox on Aug. 19, giving Boston 10 days to either trade or release the 31-year-old.
Last week, Bellhorn cleared waivers, declining Boston's invitation to report to Triple-A Pawtucket. He was then placed on release waivers, making him eligible to sign elsewhere as a free agent on Tuesday.
Bellhorn will become the second player let go by the Red Sox to join the Yankees this season, reuniting with Embree. As for bolting one side of the rivalry for the other, Bellhorn believes it will be a unique perspective.
"I don't think it's the players as much as the fans that create the rivalry," he said. "It will be interesting to see it from the other side."
Bellhorn was one of the sparks for the Red Sox during their title run last fall, hitting a big three-run home run against the Yankees' Jon Lieber in the ALCS. He also belted a game-winning homer in Game 1 of the World Series against the Cardinals' Julian Tavarez.
Boston signed him for $2.75 million to play second base, but he struggled at the plate during the first half, hitting .221 with six home runs and 27 RBIs before the All-Star break.
On July 17, Bellhorn injured his left thumb while diving for a ball hit by Jason Giambi, landing him on the disabled list. Three days later, the Red Sox acquired Tony Graffanino, who has been starting at second base for Boston ever since. With Alex Cora filling the role of a serviceable backup, the Red Sox decided they didn't need Bellhorn on the roster anymore.
He was sent on a Minor League rehab assignment on Aug. 1, where he remained until he was designated for assignment less than three weeks later.
Despite his offensive struggles this season, Bellhorn still possesses a solid glove at second, and can also play third base and shortstop. Bellhorn has even played games at first base and all three outfield positions in the past two seasons.