The speedy 24-year-old hit .294 in 20 games but made four errors in 58 chances. He saw time at second base, shortstop, third, left field and right.
"We've asked Nuney to do some things that you usually ask more of a veteran player to," Yankees manager Joe Girardi said. "For the best interest of him and us in moving forward, we thought it was probably more important that he goes down and plays shortstop six days a week and maybe second a day a week. Get him back to playing every day."
Eric Chavez was activated from the disabled list and was in the starting lineup at designated hitter for a series opener against the Seattle Mariners. Chavez had been on the seven-day concussion DL since May 3.
He was hurt the day before diving for a double down the third-base line by Baltimore'sJ.J. Hardy. Chavez says he had been working out since Tuesday and has no concussion symptoms.
Nunez, assigned to Triple-A Scranton-Wilkes-Barre, is viewed as a future starter but has struggled in the field. He had 20 errors with the Yankees last season.
"We've asked him to have so many different arm angles from the different positions that we've had," Girardi said. "We talked about it and said, you know what, maybe we're asking this kid to do too much at this time in his career. Let's get him back to doing what he's used to doing."
On Thursday, Nunez misplayed a grounder by Tampa Bay's Brandon Guyer and made a throwing error from third base. On April 19, he had a throwing error at second against Minnesota, and on April 7 he bobbled a grounder to shortstop for an error at Tampa Bay.
Playing left because of an injury to Brett Gardner, Nunez misjudged Nick Johnson's routine fly ball on May 1 and allowed it to fall for a two-run double -- a play originally called an error but overruled by MLB executive vice president Joe Torre.
"There was days he didn't know which glove he needed," Girardi said.
- Girardi said Gardner won't swing a bat until May 20 at the earliest.