The surgery was performed in Los Angeles by specialist Dr. Neal ElAttrache, known for his experience with Tommy John surgeries.
Perez, a six-time All-Star, injured his right arm during a workout on Feb. 27, and an MRI exam the following day diagnosed damage to the ulnar collateral ligament. He batted a career-low .235 last season but matched his career highs of 27 homers and 80 RBIs while playing in 129 games.
"Unfortunately injuries are a part of the game," Royals general manager Dayton Moore said in a statement on Wednesday. "We fully expect Salvy to return to our club once healthy and continue to play with the passion and enjoyment that he has played with since joining our organization."
While participating in on-field activities with his new team, Harper hit a home run off teammate Jerad Eickhoff. The blast to right field came in a hybrid simulated game and live batting practice session with Eickhoff pitching at what appeared to be full speed without a protective screen in front of him.
Harper is expected to make his spring debut with the Phillies on Saturday.
--Los Angeles Dodgers left-hander Clayton Kershaw played catch again, but the team still has not announced a timetable for when the three-time Cy Young Award winner will throw from a mound.
Kershaw's spring training preparation has been slowed by inflammation in his pitching shoulder. Manager Dave Roberts already has conceded that Kershaw, 30, will not pitch on Opening Day, ending his club-record streak of starting eight consecutive season openers.
With Kershaw not starting in the season opener three weeks, the Dodgers are left to come up with an alternate plan. The Dodgers could go with veteran left-hander Rich Hill on March 28 against the Arizona Diamondbacks, or they could pitch young right-hander Walker Buehler.
--Boston Red Sox right-hander Steven Wright has been suspended 80 games without pay after testing positive for a performance-enhancing substance, Major League Baseball announced.
The 34-year-old Wright tested positive for Growth Hormone Releasing Peptide 2 (GHRP-2), according to the league, a violation of MLB's Joint Drug Prevention and Treatment Program. The suspension starts with the beginning of the 2019 regular season.
Wright was likely to fill a role for the Red Sox this season as a multi-inning reliever. The knuckleballer appeared in 20 games last season with four starts, and a 3-1 record and a 2.68 ERA in 53 2/3 innings.
--New York Yankees manager Aaron Boone said he expects veteran left-hander CC Sabathia to start the season on the injured list.
Sabathia, 38, who is heading into 19th major league season, could miss as many as two starts at the start of the season, pushing his 2019 season debut to the middle of April. Boone told reporters that an offseason angioplasty and knee surgery have delayed Sabathia's preparation for the season.
--Houston Astros third baseman Alex Bregman left the team's spring training game against the Miami Marlins because of back stiffness.
Bregman will sit out Thursday but could return to the lineup as soon as Friday, Astros manager A.J. Hinch told reporters.
--The Texas Rangers signed closer Jose Leclerc to a four-year deal that includes options for 2023 and 2024.
The hard-throwing right-hander struck out 85 batters in 57 2/3 innings and posted a 1.56 ERA and 0.85 WHIP in 2018, collecting 21 saves in 59 relief appearances. He was named the franchise's Pitcher of the Year last season.
--Right-handed reliever Bud Norris, who appeared in 64 games last season for the St. Louis Cardinals, has signed a minor league contract with the Toronto Blue Jays, the team announced.
--Arizona Diamondbacks reliever Silvino Bracho will have Tommy John surgery and miss the 2019 season, the team announced.
--Oakland Athletics catcher Chris Herrmann needs arthroscopic surgery on his right knee and likely will miss the start of the season, according to a report from the San Francisco Chronicle.
--Controversial former Oregon State standout pitcher Luke Heimlich, who was shunned by all 30 major league teams in each of the past two drafts due to a guilty plea for molesting his niece when he was 15, signed a contract with a Mexican League team, ESPN reported.
--Major League Baseball and the MLB Players Association are reportedly nearing an agreement to expand active rosters by one to 26 players in 2020.
--Field Level Media