ST. LOUIS -- Catcher Jason Kendall took a big step toward returning to the Royals on Sunday by flying to Arizona to further the rehabilitation process of his right shoulder.

Kendall last played on Aug. 30 when his aching shoulder forced him out of the lineup. He underwent extensive surgery on Sept. 3 in Los Angeles and has been on the disabled list ever since.

At the Royals' training facility in Surprise, Ariz., Kendall will play for the Rookie classification team in the Arizona League, which opens on Monday.

Kendall, who'll turn 37 next Sunday, joined the Royals as a free agent for the 2010 season and batted .256 in 118 games. He's regarded as an excellent defensive catcher and game-caller.

He had ambitiously set Opening Day as a goal for his return, but he didn't recover as quickly as he'd hoped. When he does return, it'll be his 16th Major League season.

Duffy's excellent outing ends early with cramp

ST. LOUIS -- Royals left-hander Danny Duffy was a strikeout machine on Sunday until he suddenly broke down.

Duffy was taken out of the game because of cramping in his left calf after the Cardinals' Pete Kozma singled with two outs in the fourth inning of the Royals' 5-4 loss.

"It's just a cramp, it's not a strain or anything," manager Ned Yost said.

When he left, Duffy had registered nine consecutive strikeouts while getting 11 outs as the Cardinals seemed largely baffled. Not so baffled, however, that they couldn't score two runs with three hits and a walk in the first inning.

Yet, after Colby Rasmus flied to left for the Cardinals' first out, the next nine outs came on strikes, all but two swinging. That string was broken when opposing pitcher Jaime Garcia grounded out to short. That was followed by Kozma's single to left and Duffy's departure.

"It just grabbed me a little bit. I didn't really expect to come out but it's just one of those things -- you've got to err on the side of caution," Duffy said.

"Growing up, I used to wonder why pitchers would come out with blisters -- that's not who I am. I'd be out there with a broken leg. The last thing I want to do is use up our bullpen the way I did today. It's just unfortunate it happened the way it did, but I'll hydrate really well next time."

The game began in 83-degree heat laced with St. Louis' famous humidity.

The glut of strikeouts came on 90 pitches (56 strikes) in Duffy's 3 2/3 innings.

"In terms of being a big league pitcher, he got away with a lot of pitches up," Yost said. "He was behind in the count. He needs to take that stuff, lower it in the strike zone, keep his pitch count manageable, which he didn't do. But, yeah, he's got all the makings of being a really good Major League pitcher. He just needs time and experience at this level to work it out."

Duffy said he'll take the trainers' advice and stay off the leg on Monday, but he's OK.

"I'm fine, I can go out and play catch right now," he said.

Gordon puzzled by seventh-inning plunking

ST. LOUIS -- Suspicions were raised in a 5-4 loss on Sunday when the Royals' Alex Gordon was plunked by a pitch in the seventh inning.

Was Cardinals left-hander Brian Tallet retaliating for teammate Albert Pujols being brushed back before hitting a home run in the fifth inning, then being injured in a collision with Wilson Betemit?

Gordon was a bit puzzled because at the time the Cardinals had a one-run lead, 4-3, and he was leading off the inning.

"The first one went behind me and wasn't even close. I thought it was just an accident, trying to come inside and missed. The next one wasn't even close, either, so I was kind of surprised they hit the leadoff guy in that kind of a game with the meat of your lineup coming up," Gordon said.

The retaliation theory really didn't make much sense considering that Tallet, in fact, was brought in expressly to face the left-handed-hitting Gordon in a tight game.

"If it was on purpose, I mean what is your retaliation? What are you retaliating -- that Albert got hurt at first on a clean play? Or that there was a pitch inside that almost hit Albert that didn't?" Gordon said. "I'd say, 'Quit being a bunch of babies.'"

Royals on verge of getting two hurlers back

ST. LOUIS -- What's the next step for starting pitchers Bruce Chen and Kyle Davies?

Royals manager Ned Yost said he couldn't be sure until after he conferred with general manager Dayton Moore.

"The options are send both of them back for another rehab start, bring one back or bring 'em both back," Yost said.

One piece of the puzzle was moved after Sunday's 5-4 loss to St. Louis when pitcher Vin Mazzaro was optioned to Triple-A Omaha. He leaves with a 1-1 record and a 9.25 ERA but with a good recent history.

"It looks to me like he's starting to get on a bit of a roll, which is good," Yost said. "He threw the ball much better, still has some things to work on -- finishing hitters off. His strike one and his fastball got a lot better."

In his last start on Saturday night against the Cardinals, Mazzaro pitched six innings and gave up three runs, keeping the Royals in the game. In his previous outing, he threw seven shutout innings against the Angels.

"We've got these guys coming back and had to make room," Yost said.

The Royals said they'll make a corresponding move to replace Mazzaro on the 25-man roster before Tuesday's home game against the Diamondbacks.

Rookie left-hander Danny Duffy, who started against the Cardinals in Sunday's 5-4 loss, might also be a candidate for the Minors if the Royals decide he needs to work more on his command.

Chen pitched five innings (89 pitches) for Omaha and Davies went six innings (76 pitches) for Northwest Arkansas in injury rehabilitation outings on Saturday night. Both emerged healthy, according to reports that Yost received.

Another injured starter, Sean O'Sullivan, is scheduled to make his first rehab start on Wednesday for Omaha. He's getting over right biceps inflammation.

Yost is happy with the bullpen as it's now constituted although one reliever could be sent to the Minors if the pitching staff is reduced from the current 13 to the more normal 12.

"The bullpen has been pretty special," he said.

The club eventually could use a middle infielder to back up shortstop Alcides Escobar and second baseman Chris Getz.

Butler starts at first base in finale

ST. LOUIS -- Shades of Yogi Berra.

Ned Yost was asked if he had planned all along to play Billy Butler at first base on Sunday against the Cardinals. It wasn't exactly a 50-50 proposition apparently.

"I was 45-65," said the Royals' manager.

That math is akin to Berra's famous quote: "Baseball is 90 percent mental, the other half is physical."

Royals' outfield arms are weapons

ST. LOUIS -- Just 72 games into the schedule, the Royals' outfield already has surpassed last season's assist total for all 162 games.

The club, which has 23 assists from the outfield, surpassed last year's total of 21 on Saturday night with left fielder Alex Gordon and center fielder Melky Cabrera each getting one.

Right fielder Jeff Francoeur nailed Daniel Descalso as he tried to take second base in the ninth inning on Sunday.

Gordon and Francoeur have eight assists, tying them for second in the Majors behind Shin-Soo Choo's nine. Cabrera has seven assists. The Royals began the day leading the league in outfield assists.

The Royals' outfielders have been involved in helping nab 12 runners at the plate this season.