SURPRISE, Ariz. -- Catcher Manny Pina arrived at the Royals' camp on crutches Thursday, and he'll be leaving for Kansas City this weekend to undergo knee surgery.

Manager Ned Yost said that Pina suffered a torn meniscus in his right knee during a batting practice mishap on Wednesday. He's expected to be out at least four weeks.

"The extent to what we're looking at time-wise will be determined when they get in there and see where it's at and how bad it's torn," Yost said.

Pina might return to KC on Sunday with Dr. Vincent Key, the head team physician, and undergo surgery at the University of Kansas Medical Center.

The injury means that Brayan Pena, with whom Pina was competing for a job, likely will open the season as the backup to regular catcher Salvador Perez. Pina's injury deals a blow to the Royals' catching depth.

Other catchers still in camp are Cody Clark, Max Ramirez and Julio Rodriguez. Minor League catchers Ben Theriot and Ryan Eigsti will be shuttled in as needed. Of those five catchers, only Ramirez has any big league experience.

Pina was injured on a routine play while catching during batting practice.

"There was nothing he could have done. It was a fastball and a pitch where he shifted a little bit on a foul ball. He moved and his spike caught," Yost said. "It was one of those freak things."

Left-hander Mijares still waiting for passport

SURPRISE, Ariz. -- Left-handed pitcher Jose Mijares might be arriving from Venezuela soon. At least that's the Royals' hope.

Mijares missed the first three practices for Royals pitchers and catchers because of what manager Ned Yost described as family issues and difficulty in having his passport delivered. Mijares was hoping to receive the passport on Thursday.

"As soon as he gets his passport he'll be on his way," Yost said.

Yost said the Royals understand that the problem was beyond Mijares' control and confirmed that the player would not be disciplined or fined for reporting late. A former Twins reliever, he was signed partly for his efficiency against left-handed batters.

"Just work it out, get him here and let's get going," Yost said.

Shortstop Alcides Escobar checked into camp on Thursday, leaving only infielder Yuniesky Betancourt missing. The infielders' and outfielders' reporting date is Friday and their first official workout is Saturday.

Illness spreads through Royals' clubhouse

SURPRISE, Ariz. -- "It happens every spring," Kansas City manager Ned Yost said.

And he wasn't referring to the 1949 baseball movie by that name starring Ray Milland, Jean Peters and Paul Douglas. The movie was played for laughs, but Yost was talking about a more serious matter -- an illness spreading around the Royals' clubhouse.

It's taken the form of an upper respiratory ailment that has claimed outfielder Mitch Maier and infielder Chris Getz as its latest victims. Both were feeling the effects on Thursday. Earlier in the week, pitcher Jake Odorizzi was struck but he recovered to pitch in batting practice as scheduled on Wednesday.

"I felt a little sick but everything went OK," Odorizzi said.

Yost is hoping the bug doesn't continue to bite his players.

"It started with [Everett] Teaford," Yost said. "That was ground zero as far as I know. It happens every spring. Somebody gets sick and it spreads. Every club goes through it. I've never been through a Spring Training where it doesn't happen."

The movie? It's about a college professor who stumbles upon a chemical compound that repels wood. Soak a baseball in it and, yep, it skips right around a bat. You can see where that plot is going and, sure enough, the prof uses the miracle potion to pitch St. Louis into the World Series.

Yost plans to break camp with 12 pitchers

SURPRISE, Ariz. -- The Royals have 30 pitchers on their Spring Training roster, and that will be whittled down to a dozen by Opening Day on April 6. But manager Ned Yost realizes that, in the end, he'll need many more pitchers than that by season's end on Oct. 3.

"Don't set it in stone but, in my mind right now, we're going break this camp with 12 pitchers," Yost said. "Last year we used 22 pitchers over the course of the year. So competition doesn't stop at the end of camp. We're going to need between 20 and 25 pitchers to reach where we want to go. So, is it going to hurt in Spring Training when you're not part of that 12? Yeah, but do not take yourself of that 20 or 22 group because you will get an opportunity to come up and help us."

Many of the pitchers, and some position players as well, have options remaining so it's easier to move them freely between the Majors and the Minors as needed.

"When you get into a position where you need to compete and you've got a guy that's struggling and he's got options, odds are you make changes a lot quicker than we have in the past," Yost said. "I imagine that's probably what we're going to do here. You'll give everybody an ample opportunity but you're not going to get three weeks to work yourself out of it. You'll get a week or 10 days and if you're not out of it, you'll find yourself working yourself out of it in Omaha."