The Yankees don't get a ton of mileage out of their starting pitchers, which places an unusually heavy toll on their bullpen. To compensate, they've started to rely more heavily on their Minor League system.
"Because of some of our concerns about the length we get, we kind of rotate people in and out here a lot," Girardi said. "And it doesn't mean we don't believe in them. We're doing it to kind of protect the arms of everyone."
They've done so at a historic pace. With Moreno tossing a scoreless inning Monday, the Yankees have now used 21 different pitchers in June alone, a club record for a month when excluding September and its expanded rosters.
Right-hander Danny Burawa and left-hander Jose De Paula, who each pitched Sunday, were optioned to Scranton/Wilkes-Barre as part of the move.
Moreno, 27, had a 2.27 ERA in 35 2/3 Triple-A innings this season. He's slowly worked his way through the Minors after signing with the Pirates in 2006. The Yankees acquired him as part of the trade that sent A.J. Burnett to Pittsburgh in 2012.
Rumbelow, 23, was the Yankees' seventh-round selection in the 2013 Draft. He sped his way through four levels of the Minor League system in 2014 and has spent all of '15 at Triple-A, where he's tallied a 3.31 ERA in 35 1/3 innings.
"If the big league team needs somebody, we're down there working hard," Rumbelow said. "Hoping to come up and contribute."
Both are high-strikeout right-handers. Girardi hopes they can fill a void of that kind of pitcher in the middle of his bullpen.
"We've kind of settled in on who our seventh-, eighth- and ninth-inning guy is; we've looked for a right-hander to help us in those situations," Girardi said. "That has been ever-changing, and that's who we're looking for."
Alden Woods is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.