McDonald, who was designated for assignment by Boston on Saturday, will join the Yankees' active roster on Friday, when they start a four-game weekend series at Fenway Park against the Red Sox. With Boston starting three left-handers in four days and a day-night doubleheader scheduled for Saturday, Yankees manager Joe Girardi expects the right-handed-hitting McDonald to play this weekend.
"We're going to see three lefties," Girardi said. "He's going to play the outfield some this weekend."
The Yankees will have to make a corresponding move on the 25-man roster when McDonald is activated, but Girardi mentioned the possibility of putting Andruw Jones at designated hitter or giving center fielder Curtis Granderson one of Saturday's games off.
A fan favorite in Boston, McDonald batted .214 with a .678 on-base plus slugging percentage this season, hitting two homers and collecting nine RBIs while playing all three outfield positions.
McDonald first announced the move on Wednesday afternoon on his Twitter account, @MacDime54, saying he "just got off the phone" with Yankees general manager Brian Cashman and was "happy to announce I'm a new Member of the N.Y.Y."
To make room for McDonald on the 40-man roster, the Yankees designated right-hander Chris Schwinden for assignment.