"I just feel more comfortable using [Robertson] for an inning right now," Girardi said. "I don't think he has any physical problems. It's just something I'm more comfortable doing."
Girardi said that he may relax those restrictions for Robertson later in the season, partially because he can envision using Robertson more frequently than when was the setup man to Mariano Rivera.
"As the closer, a lot of times you can get more than two days in a row," Girardi said. "If he feels good, I'd like to use him the third day. As much as you can, you try not to get caught without having your closer. It's a long year, and it's still really early. He had a couple weeks off, and I just have to make sure that he's built up right."
Bryan Hoch is a reporter for MLB.com. Follow him on Twitter @bryanhoch and read his MLBlog, Bombers Beat. This story was not subject to the approval of Major League Baseball or its clubs.