Robertson injured his groin a little more than two weeks ago. At the time, Yankee officials and Robertson thought he would just need the 15 days on the DL.
After a tune-up at the Yankees' spring training facility in Tampa, Fla., this weekend, Robertson declared himself ready to return.
Robertson has two saves in two opportunities and has yet to allow a run in three innings. He is replacing baseball's all-time saves leader, Mariano Rivera, as the Yankees' closer this season.
In Robertson's absence, Shawn Kelley picked up four saves. The right-hander will now return to the eighth-inning role on most days.
The Yankees made some other roster moves in their bullpen, optioning Matt Daley and Bryan Mitchell to the minors. The team also announced that left-hander Cesar Cabral passed through waivers and will report to Triple-A Scranton.