KANSAS CITY -- Third baseman Josh Fields and catcher Lucas May joined pitcher Gil Meche as callups to the Royals as Major League rosters expanded on Wednesday.

Additional callups could come later but one player not likely to be added is the Royals' hottest hitting prospect, third baseman Mike Moustakas. On Monday night, just after being named Texas League Player of the Year, Moustakas continued his big season for Triple-A Omaha with a three-homer, 11-RBI game.

"You could certainly make a case that it's important for him to come up here in September, get acclimated and see what the Major Leagues are about," Royals general manager Dayton Moore said. "Is that prudent now? It's not. He's still going to get the same opportunity in Spring Training that he would have had in 2011 whether he's a September callup or not."

To be called up, Moustakas would have to be added to the Royals' 40-man roster, beginning to accumulate Major League service time at a big league salary scale. There are other considerations: Moustakas is seen as probably starting next season with Triple-A Omaha and, to protect him from the Rule 5 Draft, he wouldn't have to go on the Royals' roster until after the 2011 season. Also, being on the 40-man roster would prevent him from playing this fall on Team USA in the Pan American Games. He is also scheduled to play in the Dominican Winter League to get additional at-bats.

And, of course, third base will be amply populated by Fields, who was obtained last winter from the Chicago White Sox as a right-handed power hitter, and Wilson Betemit, who has been hitting well since taking over for the traded Alberto Callaspo.

Fields, rehabbing from hip surgery with Double-A Northwest Arkansas, is 15-for-35 (.429) in 10 games with six doubles and seven RBIs. His right hip seems sound -- he's twice scored from first base on doubles -- and has been agile playing at third.

"The numbers have been great and he's healthy," Royals manager Ned Yost said. "He's moving fine so the next step for me is I want to see him with my own eyes. I've heard that when he's healthy, he's a decent defender at third base."

May was acquired from the Los Angeles Dodgers on July 28 in the trade for outfielder Scott Podsednik. For two Pacific Coast League teams, Albuquerque and Omaha, May has hit .291 with 16 homers and 58 RBIs in 97 games.

"He's going to be out of options next year and this would be a chance to see him at the Major League level," Yost said.

May was struck by a bat on the arm by a backswing and had to leave Monday night's game but is expected to be OK to report to the Royals.

Meche, a Royals starter for most of four years, opted to forego shoulder surgery and instead will try to pitch in relief. The Royals also will get starters Brian Bannister and Luke Hochevar back from rehab assignments shortly and reliever Robinson Tejeda was just reactivated.

With all those returning arms, Yost said that pitching would be not be a callup priority. In fact, he doubted left-handed relief standout Tim Collins would be promoted from Omaha where he's continued a high-strikeout season with 19 whiffs in 18 innings and a 1.50 ERA in 12 games.

Duffy to play in Arizona Fall League

KANSAS CITY -- Left-handed pitcher Danny Duffy, who got a late start on his season, will be among the Royals' Minor Leaguers who will play in the Arizona Fall League beginning on Oct. 12.

The others who were announced on the Surprise Rafters roster on Tuesday were right-hander Patrick Keating and left-hander Mike Montgomery; catcher Salvador Perez; second baseman Johnny Giavotella and first baseman Eric Hosmer, and outfielder Derrick Robinson.

All are on the Double-A Northwest Arkansas roster except Perez, who is with Class A Wilmington. Another pitcher will be added later.

Duffy, a top starting prospect, left Spring Training for personal reasons but later decided to return to pitching. In 13 games for three Minor League clubs this season, he's 4-3 and has a 2.98 ERA. For Northwest Arkansas, he's 4-2 with a 3.38 ERA.

Royals' Texeira to resume throwing

KANSAS CITY -- Royals reliever Kanekoa Texeira, out with a strained right elbow, hopes to resume throwing as soon as Friday.

Texeira was added to the Royals' disabled list on Sunday.

"My arm was hurting for a while but that's part of the game - you never feel 100 percent," he said. "But my arm got to hurting so bad I couldn't keep the ball down."

After being claimed on waivers from Seattle on June 3, Texeira pitched in 27 games for the Royals with a 6.00 ERA. But he was hit hard in his last five appearances, giving up 15 hits and 10 runs in nine innings for a 10.00 ERA.

He was used primarily as a middle-inning reliever.

Worth noting

The 10-9 win over the Rangers on Tuesday night was the Royals' sixth walk-off victory this season and made them 25-25 in one-run decisions. ... Winning pitcher Joakim Soria not only got his first victory this season against two losses, he extended his string of scoreless innings to 15. He hasn't allowed a run since July 28 against Minnesota. .... Yuniesky Betancourt's 14th home run, his career best by five, was his seventh during August. .... Alex Gordon's three RBIs matched his season high, achieved on July 30 when he hit a walk-off home run against Baltimore. .... Cliff Lee's career record against the Royals remained at 12-5. His 4 2/3 innings marked his shortest start since Sept. 20, 2009, when he worked four innings in a rain-shortened appearance for Philadelphia at Atlanta. .... The Royals had an 11-15 record in August.