Giese blanked the Angels for three innings on Sunday, and has posted a 1.35 ERA since the start of July. Though he started two games earlier this season with mixed results, Giese has not pitched out of the rotation since June.
In 13 starts for Triple-A Scranton before joining the Yankees in early June, Giese produced a 4-2 record and 1.98 ERA, striking out 51 batters in 59 innings.
"I like starting," Giese said. "I'm comfortable doing it."
Rasner, meanwhile, has struggled for the better part of two months, posting a 2-8 record after beginning the season 3-0. A lack of command has hurt him in recent starts, and since the beginning of June, he has produced a 6.71 ERA. In his final start on Sunday, Rasner lasted only four innings, allowing five runs on seven hits and three walks.
"Darrell understood, and he said, 'I'll get better,' " Girardi said. "And that's what you want a player to say. We'll get him straightened out."
Promoting Giese to the rotation was by no means a simple decision. Another choice -- and perhaps a more long-term solution -- would have been Ian Kennedy, who is 3-0 with a 1.33 ERA in his past four starts for Scranton. Girardi said that he considered Kennedy for Friday's start but ultimately sided with Giese and his ability to throw strikes.
This promotion may not be permanent, either. Giese has a chance to remain in the rotation, certainly, but Girardi said Monday that he expected Phil Hughes to be back with the team by the start of September. Hughes, mending a rib-cage stress fracture, is scheduled to start Thursday for Scranton, while Carl Pavano, rehabbing from Tommy John elbow ligament replacement surgery, is slated to start that same day for Double-A Trenton.
Either of those two pitchers could be in the rotation by season's end.
For now, it will be Giese, who will have most of his immediate family in Anaheim on Friday. Giese, a native of Riverside, Calif., could potentially pitch one more relief inning on Wednesday in lieu of a side session and will be limited to roughly 85 pitches in his first start.
"I was just pitching," Giese said of his recent success. "I wasn't looking ahead, looking back. It was just one pitch at a time. It's really as simple as that."