KANSAS CITY -- The Royals will be without their veteran catcher for an extended period of time, as the club announced Friday that Salvador Perez had successful surgery to repair the ulnar collateral ligament on his left thumb.

Perez is expected to return to play this season; manager Mike Matheny said the timeline Royals trainers are eyeing is around eight weeks for Perez¡¯s return.

¡°We¡¯ll use that as a template right now, but you always have to wait and see how he feels, how the recovery starts to go,¡± Matheny said before Friday's series opener against the A¡¯s. ¡°Normally when I hear anything about the thumb, and you hear [the word] 'surgery,' I was anticipating we wouldn¡¯t have him the rest of the season. Anything we¡¯re hearing that¡¯s sooner than that is good news for us.¡±

Perez was sidelined in May with a left thumb sprain after he injured his thumb swinging. He returned after 10 days and served as the Royals¡¯ primary catcher for a month before he felt the same injury again on Tuesday in Anaheim. He sat out of the lineup for Wednesday¡¯s series finale while the Royals awaited MRI results to determine the next steps.

Unfortunately for the catcher, who had been looking for his eighth All-Star appearance, surgery was the recommendation. Perez is slashing .211/.254/.426 this year, with a team-leading 11 home runs. It did take him some time to get going at the plate after he returned the first time -- he had been wearing a brace on his thumb -- but he was hitting .246 in his last 15 games, with three homers and 12 RBIs.

¡°Salvy was wrecked,¡± Matheny said of Perez's reaction to the setback. ¡°I don¡¯t need to convince anybody about how passionate this guy is about playing the game of baseball. Any time an injury like that happens, you just don¡¯t know. He was on such a good track, coming back and getting strong, watching the ball jump out of the park and carry, everything seemed to be going well. And one swing sent him in a bad direction. Fortunately, the procedure went well, and we move forward.¡±

Perez was placed on the 10-day injured list, and in his place on the roster the Royals reinstated outfielder Edward Olivares from his rehab assignment at Triple-A Omaha, where he had been working back from a right quad strain. Olivares went on the injured list when he was seizing everyday playing time with a .907 OPS in 15 games. He played nine games in Omaha on a rehab assignment and posted a .697 OPS.

The 26-year-old slotted right back into the lineup on Friday, hitting eighth and playing right field.

Olivares will likely get more time in right field, along with Kyle Isbel, because MJ Melendez will be the primary backstop in Perez¡¯s absence. The Royals had a logjam before, trying to get Melendez and Perez in the lineup every day, but Melendez will now take over the starting catching role with Cam Gallagher as a backup.

¡°MJ has improved so much since the first time we had him [behind the plate],¡± Matheny said. ¡°Just watching his progression. How he¡¯s handling the staff and the preparation, handling all the information and understanding the rhythm of what he needs as far as film work, understanding the data, and then what each of the pitchers are looking for, too, I think that¡¯s as much as any of it. ¡­

¡°He¡¯s making all the right progressions as far as game planning, and he¡¯s looking more comfortable every time he gets back there, too.¡±