Loaisiga will start throwing on Friday, manager Aaron Boone said on Thursday.
Loaisiga, who received a cortisone shot when he was placed on the IL, had been the Yankees' most reliable reliever before going down.
In 68.0 innings this season over 54 appearances, Loaisiga has a 2.25 ERA (2.59 FIP) and 1.02 WHIP with 66 strikeouts.
But Chapman, back in the closer role, has mostly excelled since Loaisiga landed on the IL.
Since allowing one run on Sept. 8, Chapman is unscored upon in his last four appearances, having allowed just two hits and one walk while striking out seven in 3.2 innings.