The move means that Benintendi won't be able to face his former team when the Royals host the Boston Red Sox this weekend.
"He had something grab when he threw yesterday [against the Oakland Athletics] with the ball off the wall," Royals manager Mike Matheny told reporters, according to the Kansas City Star. "He'd been feeling a little bit of something for a while. Obviously, it wasn't affecting his swing. On the throw, it grabbed him. He was fine last night. Woke up today and it wasn't right. He had it X-rayed."
Benintendi, who was traded by the Red Sox to the Royals before the season, is hitting .283 with eight home runs and 31 RBIs in his first season with Kansas City.
He missed most of the pandemic-shortened 2020 season because of a strained right rib cage.
The Royals recalled outfielder Edward Olivares from Triple-A Omaha in a corresponding move.