Hosmer will miss the entire three-game series against the Indians. He was injured on Thursday at Detroit, when he dove for a triple whistled down the right-field line by the Tigers' Quintin Berry. That happened in the second inning and Hosmer left the game an inning later.
He underwent an MRI on Friday.
"There's a slight tear in the rotator cuff," Hosmer said. "So basically we're just going to wait until we get back to Kansas City and do all the testing and stuff again there, and see how it feels and go from there."
It's his non-throwing shoulder so the obvious concerns are catching the ball and swinging a bat. Hosmer downplayed the extent of the injury.
"Not very serious, it's not going to need surgery or anything like that," Hosmer said. "It's something that heals on its own so there's no cutting involved. ... It's going to rehab on its own and be good to go."
Shortstop Alcides Escobar also sustained a right shoulder injury in Thursday's game, getting bruised as he dove for a bloop hit in short center field, and he was not in the starting lineup for the first two games in Cleveland. Escobar said he passed MRI scrutiny and is ready to play.
However, manager Ned Yost opted to have backup infielder Irving Falu at shortstop on Saturday night. Billy Butler, usually the designated hitter, again took Hosmer's spot at first.
Is Hosmer through for the season? After all, when the Royals return to Kansas City, they have just three games left against the Tigers and that's it.
"I don't know, to be honest with you, I think we're going to know about it when we get back to Kansas City and do the re-evaluation, but it's all up in the air right now," Hosmer said.
Yost will wait to see what the test results are in KC and how Hosmer feels on Monday.
"It's a moderate strain, they call it," Yost said.
At this late point of the season, it's expected that the Royals medical staff will be cautious about injuries.
"They should be but there's going to come a point [in future seasons] when we're going to be competing and we're going to need guys to play," Yost said. "So we've got to find out what our limits are, but we're not going to do anything stupid either."