Nishioka injured his ankle sliding into third base on a triple on Friday. He was hitting .203 with eight walks in 16 games before the injury.
"Nishi has a high ankle sprain, but I'm not sure how many days [he'll be out]," manager Ron Gardenhire said. "So right now, [Brian] Dozier is the main guy in the infield. We'll let him get more at-bats."
Nishioka, 27, was optioned to Triple-A during Spring Training. It came after he struggled last season, hitting just .226 with five doubles in 68 games. He also made 12 errors in the field, including 10 at shortstop and two at second base.
Nishioka is in the second year of a three-year deal worth $9.25 million, but he has been passed up on the depth chart by Dozier, who was the club's Minor League Player of the Year last year.
"He's definitely the top guy down there," Gardenhire said. "There's no doubt about that."