The deal is expected to be for one-year and $12 million, according to officials with knowledge of the talks.
Youkilis, who will turn 34 in March, will play third base for the Yankees in place of the injured Alex Rodriguez. In 2012, Youkilis hit .235 with 19 homers and 60 RBIs in 111 games. After feuding with then-Boston manager Bobby Valentine, Youkilis spent most of the season with the Chicago White Sox.
The Yankees are expected to add another veteran by the end of the week. Outfielder Ichiro Suzuki's agent and the team are finishing up the details on a one-year contract, sources said Monday.
Both Youkilis' contract, Ichiro's expected agreement and the already finalized contracts with Mariano Rivera, Andy Pettitte and Hiroki Kuroda do not add any money toward 2014. The Yankees are working to fall under the $189 million payroll mark by '14 to take advantage of luxury tax and revenue sharing that could net them around $50 million.
Youkilis was not the Yankees' first choice at third. Going into the winter meetings, the Yankees' hoped to sign a platoon of Jeff Keppinger and Eric Chavez. Instead, Keppinger inked a three-year deal with the White Sox, while Chavez took $3 million, on a 1-year contract with the Arizona Diamondbacks.
The Yankees did not formally offer either a contract.
In his days with the Red Sox, Youkilis did not have a great relationship when competing against the Yankees. Most notably, he and Joba Chamberlain went back and forth with Chamberlain often pitching inside or hitting Youkilis.
With Rodriguez due to have a second hip surgery in January, Cashman made upgrading third base a top priority of the offseason. The Yankees hope Rodriguez can return by June, but he may be closer to the All-Star break, at best.
When he does return, it is unknown if he will be able to play defense. In 2012, Rodriguez already played one-third of his games as the DH. Yankees manager Joe Girardi said at the winter meetings that whomever the Yankees acquire to fill-in for Rodriguez that player should be prepared for a full season on defense.
Youkilis has had his own troubles with a bad back. The past three seasons he has averaged 115 games per year.
Information from ESPN The Magazine's Buster Olney was used in this report.