KANSAS CITY -- All-Star catcher Salvador Perez will be placed on the 10-day disabled list after suffering an intercostal strain during the Royals' 5-2 loss to the Mariners on Friday night.
With Saturday's game rained out, the Royals waited until Sunday to make the move. They wanted to see if Perez would make what manager Ned Yost called "a miraculous recovery." Catcher Cam Gallagher was added to the 25-man roster in a corresponding move.
Perez is eligible to return on August 15, since he was placed on the DL retroactive to Saturday. Yost said the best-case scenario is Perez will be out for 10 days. The worst-case scenario is a longer time frame: four weeks. The Royals will have a more precise timeline on Monday or Tuesday.
"What happens is these things get swollen and full of fluid," Yost said. "You have to give it some time to get out of there, so you can really take a good look at the extent of the injury."

Perez's injury came with the Royals 2 1/2 games behind the first-place Indians in the American League Central and a half-game ahead of the Rays for the second AL Wild Card spot.

Perez underwent an MRI on his right side after he struck out to end the sixth inning of Friday's loss. He appeared to wince after his swing, and he was replaced by backup catcher Andrew Butera.
Earlier this season, Perez was selected to his fifth overall and fourth straight All-Star Game. He is batting .278, and he leads all catchers with 21 home runs and a .510 slugging percentage this season.
In Perez's place, Butera will step in as the starting catcher. He has played in 44 games this season, and he is batting .250 with two home runs.
"I'm always ready," Butera said. "It's unfortunate that's the way [starting] happened. You don't wish an injury on anybody, especially your teammates, and especially a really good guy like Sal."
Gallagher, the Royals' second-round pick in 2011, will back up Butera until Perez returns. Gallagher batted .294 in 68 games at Triple-A Omaha this season. He has no previous Major League experience.