SURPRISE, Ariz. -- Salvador Perez, the Royals' 21-year-old newly signed catcher, has a sore knee that caused him to be taken out of Tuesday's game after one inning.

Perez apparently was injured before the game in the left-field bullpen while warming up starting pitcher Jonathan Sanchez before the Cactus League game against the Reds.

While the Royals were beating the Reds, 7-5, Perez was taken for an MRI to determine what might be wrong.

"I'm not going to overly concern myself until I hear exactly what the deal is with him," manager Ned Yost said after the game. "But honestly I'm a little bit concerned."

Initial details were so sketchy that Yost didn't know which knee Perez had injured. He was tended by head athletic trainer Nick Kenney.

"He was down there warming up Sanchez, getting ready to bring him in the game and, quite frankly, I really don't know what happened," Yost said.

"[Catching assistant] Jason Kendall came up and said, 'Boy, Salvy's limping a little bit coming in, he might have done something to his knee.' And I walked down and the trainers were looking at him."

Although the knee was sore, Perez could get into his crouch so he was permitted to catch the first inning, then was taken out of the game.

"You know a lot of it this time of year is precaution so I don't know the extent of it. I know it was sore and they wanted to get him out of there right away and find out what it was," Yost said.

If Perez is out for a while, the Royals will have to rely on backup Brayan Pena. They already have lost the third catcher on the Major League roster, Manny Pina, to knee surgery and he'll be out for the rest of Spring Training.

Perez was replaced on Tuesday by Triple-A catcher Cody Clark, who caught the rest of the game and contributed two hits to the Royals' 16-hit attack.

Perez, who was taken out before he batted, is hitless in 15 at-bats so far in the Cactus League.

On Feb. 27, the Royals signed Perez to a five-year contract that runs through 2016 with club options for each of the following three seasons, 2017-19. The contract guarantees Perez $7 million but could be worth a total of $26.75 million for the full eight years if all the options are exercised and all the incentives written into the deal are achieved.

Perez was called up from the Minors by the Royals on Aug. 10 and made an immediate impression with outstanding defensive skills and a .331 average in 39 games.

Hosmer OK, Moustakas rests bruised knee

SURPRISE, Ariz. -- Eric Hosmer was OK on Tuesday but Mike Moustakas was scratched from the Royals' lineup about an hour before the game against Cincinnati.

Moustakas had a bruised and sore right knee, the result of being hit by a pitch in Monday's game against San Francisco. He was originally in Tuesday's lineup as the designated hitter but ultimately was replaced by Hosmer, who was supposed to split the Reds game at first base with Billy Butler.

Hosmer was concerned about his right shoulder after making a diving stop of a ground ball that caromed off the bag on Monday.

"I went to dive and brought my hand out for the ball. I was already in the air and the ball hit the bag and came back," Hosmer said. "So I brought my shoulder back to catch it and then when I came down I kind of fell on it wrong. I felt a little pinch in the beginning but when I turned around and lifted it, it was completely fine. I was a little nervous -- I didn't think I'd be able to move it but now it's fine."

Hosmer and Moustakas found themselves in the dirt within minutes of each other in the fifth inning on Monday. Hosmer was on his way to the examination room with head athletic trainer Nick Kenney when Moustakas was struck by the pitch and went down.

"As we were going up the steps, that happened to Moose and Nick says, 'Wait a minute, we've got to wait for your buddy now.'" Hosmer said. "Luckily everything's OK, though. I'm sure it was a scare but everything's fine."

Moustakas, though, apparently needs a little time for his knee to heal.

Sanchez still working out kinks in control

SURPRISE, Ariz. -- Left-hander Jonathan Sanchez, still feeling his way after missing much of last season with injuries, felt satisfied with his outing on Tuesday against the Reds despite giving up four runs in two-plus innings.

"It doesn't matter what happened. I'm doing my best, throwing my stuff and I'm good," he said. "Everything feels good."

Sanchez, who figures to be one of the Royals' top three starters, threw 55 pitches and 33 were strikes. One strike was driven over the center-field wall by the Reds' Jay Bruce in the first inning.

"I missed my spot and let that fastball down the middle," Sanchez said. "But that happens once in a while. It's not going to happen again."

Sanchez gave up two runs in the first inning, one after first baseman Billy Butler missed his pickoff throw and the error allowed the runner Drew Stubbs to reach third base.

"Gonna have to get Billy working with Sanchez on the pick-off move over there because his stuff is just as wicked to first as it is to home plate," manager Ned Yost said. "I went out to the mound and Billy said, 'The ball's moving every which way.' I said, 'That's all right, I'll get Esky [shortstop Alcides Escobar] to throw you some knuckleballs and we'll practice it.'"

Sanchez was pulled after the first two batters in the third inning hit singles. He was replaced by fellow lefty Everett Teaford, who gave up two runs by allowing two hits and a walk.

"I definitely didn't want to give up Sanchez's runs, especially to a left-handed hitter [Bruce, who singled] because being a left-hander I've got to get left-handers out," Teaford said. "But I settled down and threw a couple of scoreless."

Jeremy Jeffress also zipped two scoreless innings in the Royals' 7-5 win, retiring all six batters. That gives the hard-throwing but sometimes erratic right-hander four scoreless innings with just one walk. What's he happiest about?

"The amount of strikes I've thrown because last year was pretty tough with the walks and the pitches but I was really impressed by the amount of strikes I threw today," Jeffress said.