Per MLB Network's Jon Heyman, doctors have recommended Perez have Tommy John surgery, and he's expected to undergo the procedure next week.
Per MLB.com's Jeffrey Flanagan, the Royals announced Friday their All-Star catcher will be out indefinitely after an MRI showed damage in his UCL.
The Royals said in a statement Perez suffered the injury during Wednesday's spring training workout. He will visit Dr. Neal ElAttrache in Los Angeles for a second opinion next week.
Perez has been hit by injuries in each of the previous two seasons. He missed two weeks in August 2017 due to an intercostal strain and the first 20 games in 2018 with an MCL tear.
With Perez expected to miss the entire season, Cam Gallagher will likely take over behind the plate. Kansas City will host the Chicago White Sox in its season opener March 28.
Since taking over as Kansas City's starter in 2013, Perez has established himself as one of MLB's best catchers. The Venezuela native ranks sixth among all players at the position with 14.2 FanGraphs wins above replacement over the past six seasons and tied his career high with 27 homers last season.