NEW YORK — The early explanation was that Domingo Germán had experienced discomfort near his right armpit and could not play catch on Sunday. That prompted the Yankees to scratch the right-hander from his scheduled outing Monday, summoning rookie Jhony Brito from Triple-A Scranton/Wilkes-Barre for an emergency start.

Yet once Brito had surrendered his fourth home run of the night, Germán began tossing from the bullpen mound, a display that prompted head-scratching. There was even more confusion when Germán soon entered the game, tossing five spotless innings of relief in the Yankees’ 5-1 loss to the Rays in the series opener at Yankee Stadium.

“He feels good today, but we didn’t feel like we could risk sending him out there,” Yankees manager Aaron Boone said before the game. “If we had to pull the plug in the first inning, it puts us in a tough situation.”

Brandon Lowe hit a two-run homer in the first inning off Brito, who also surrendered a solo shot to Wander Franco in the third inning before Isaac Paredes and Josh Lowe slugged back-to-back blasts in the fourth.

Brito permitted five runs on six hits in four innings before yielding to Germán, a switcheroo that had echoes of the Yankees’ attempt to surprise the Rays in Game 2 of the 2020 American League Division Series, when rookie Deivi García was a last-minute opener ahead of veteran J.A. Happ.

Jake Bauers hit a solo homer in the second inning for the Yanks, who dropped their third in four games to begin their pivotal week ahead of Tuesday’s 6 p.m. ET Trade Deadline.