Laffey made his debut for the Yankees on Saturday night, tossing three innings and allowing two runs on five hits.
"He's a guy that we believe can help us against left-handers as we move forward here," Girardi said. "He's not going to be able to throw for a couple days anyway."
Laffey will likely return to the Yankees when the rosters expand on Sept. 1. Until then, they would like him to work on a few things in Triple-A.
"I think left-handers are important for him to be consistent [against]," Girardi said. "He was consistent in getting left-handers out until the last month or so, or month and a half. So, get back to doing that."
Jordan Schelling is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.