After throwing a scoreless ninth inning, Mitchell moved to first and allowed one foul popup to fall for an error in the 10th, then caught another. He returned to the mound in relief of closer Aroldis Chapman to start the 11th and gave up run-scoring singles to Mark Trumbo and Welington Castillo in the Baltimore Orioles' 7-4 win Sunday, which stopped New York's winning streak at four.
"The whole series was kind of crazy," Yankees left fielder Brett Gardner said.
New York overcame a 9-1 deficit to win Friday's series opener 14-11 in 10 innings, then romped 12-4 Saturday. With Adam Warren and Tommy Layne unavailable after outings in the middle game, Yankees manager Joe Girardi felt a need to improvise. So when Mitchell reached the dugout in the middle of the ninth, pitching coach Larry Rothschild asked him a question out of right field: Would he move to first if the game went into extras, allowing him to return to the mound later?
"All right. I'll go get a glove. I'll be ready," Mitchell remembered responding.
Mitchell retrieved one of first baseman's Greg Bird's mitts from the clubhouse and became the first Yankees pitcher to play another position since Billy Martin petulantly put Ron Guidry in center for the finish of the Pine Tar Game against Kansas City on Aug. 18, 1983.
Sure enough, the leadoff batter hit the ball to Mitchell -- Castillo's foul pop just in front of first base. Castillo singled after Mitchell's error prolonged the at-bat, and Mitchell rebounded to glove Jonathan Schoop's foul pop for the second out -- earning a standing ovation.
"I was praying for him, to be honest with you," Yankees reliever Dellin Betances said.
Mitchell smiled at his newfound fielding ability.
"I guess I just went back too far and the ball had a lot of spin. I just never actually got there," he said. "Luckily, the next one was a little closer to me."
Girardi wasn't sure whether Mitchell ever had played first.
"I didn't ask," he said. "I have a strikeout pitcher on the mound. You don't assume there's going to be too many ground balls over there."
Even in the 11th, when he was back on the mound, Mitchell tried to keep making fielding plays.
"All of a sudden he started running after every popup," Girardi said, shaking his head.
The Yankees demoted Mitchell to Triple-A Scranton/Wilkes-Barre on Monday.
The Associated Press contributed to this report.