OAKLAND, Calif. — The Yankees’ no-longer-secret weapon is back in the bullpen.

Ian Hamilton was activated off the injured list on Wednesday after missing six weeks with a groin strain, returning to bolster a relief corps that has been the best in baseball with a 2.83 ERA.

To open a roster spot for Hamilton, the Yankees optioned Jhony Brito to Triple-A Scranton/Wilkes-Barre after he turned in another solid start on Tuesday, throwing 5 ⅔ innings in a 2-1 loss to the Athletics.

The Yankees will have to call up a spot starter on Sunday in St. Louis — likely to be Randy Vasquez — before Carlos Rodon is expected to return and fill the rotation spot the next time through on July 7 against the Cubs.

Rodon, who had been dealing with a forearm muscle strain and back discomfort, is set to make his third, and likely final, rehab start on Saturday with an affiliate to be determined. 

The 28-year-old Hamilton, who earned a spot on the roster with a strong spring training as a non-roster invitee, had posted a 1.23 ERA in 16 appearances before getting hurt.

The right-hander struck out 30 and walked nine across 22 innings, working his way into higher-leverage situations, including picking up his first career save on May 6 against the Rays.

With the return of Hamilton, the Yankees will go with a nine-man bullpen until Sunday, when they will likely have to send a reliever out for Vasquez.