Loaisiga will begin a rehab assignment with Double-A Trenton on Tuesday, Sam Dykstra of MiLB.com reports.
Loaisiga has been out since mid-May with a shoulder strain. He had thrown just 14 big-league innings this year prior to the injury, posting a 4.50 ERA and a 13:8 K:BB. He's expected to pitch exclusively out of the bullpen once activated, though the Yankees' rotation woes could put him in position to start eventually.