OAKLAND -- Designated hitter Billy Butler looks like the odd man out when the Royals play their first games on National League soil this weekend at St. Louis.

Rookie first baseman Eric Hosmer figures to be in the lineup while Butler, who led the regulars with a .302 average through Wednesday, will be on the bench as a pinch-hitter.

Hosmer was batting .288 with five homers and 22 RBIs in his first 37 games. He also was providing excellent defense.

"If the kid struggled to hit or he wasn't a run producer, it's an easy choice," Yost said. "You go ahead and take the offense [with Butler] and defend for him later but [Hosmer] is pretty good all the way around."

Hosmer was rested on Thursday for the first time since being called up on May 6. Wilson Betemit, not Butler, started at first base in his absence.

"We're looking for defense," Yost said. "Billy can play over there, [but] Wilson's best position is probably first base out of all of them."

Butler declined to talk about the situation on Thursday.

Running on Royals outfield is risky proposition

OAKLAND -- Jeff Francoeur, the Royals' strong-armed right fielder, has as many outfield assists as a piano has keys.

That's 88 assists since he broke in with the Braves in 2005, 21 more than his nearest competitor, the Cubs' Alfonso Soriano with 67.

There's more sweet music in the Royals' outfield. Francoeur and left fielder Alex Gordon each have seven assists and center fielder Melky Cabrera has six.

"I feel good with all of our outfield arms -- especially on short balls," manager Ned Yost said. "We're just kind of daring them to go."

It's not just happenstance either. The outfielders are drilled continually by coach Doug Sisson, a necessity since the old pregame ritual of "taking infield," which also included the outfielders and catchers, is virtually nonexistent today.

Teams now hit ground balls to their infielders during batting practice, but that leaves out the outfielders and catchers. The Royals fill that gap by having the outfielders throw in special workouts every three days or so, usually at the start of a series.

"Sometimes when you're in the big leagues, you can forget you need to do that kind of stuff to keep yourself going," Francoeur said. "I think [Sisson] does a great job of keeping us reminded that we need to do that and it's worked out well for us."

The Royals' combined 20 outfield assists are the most in the American League and ties the Dodgers for most in the Majors.

"This isn't a fluke. These kids work hard at their throwing," Yost said.

The catchers, Brayan Pena and Matt Treanor, also work on their throwing on the same schedule.

"Eliminate 'infield,' but continue to practice the fundamentals in the outfield and behind the plate and you still have all the benefits of infield every day without taking infield," Yost said.

Former Royal DeJesus stuck in part-time role

OAKLAND -- Former Royals outfielder David DeJesus hasn't been playing every day as anticipated when the Athletics obtained him last winter in a trade for pitcher Vin Mazzaro.

"It's the way it is," DeJesus said. "They play ... matchups. That's how [former manager] Bob [Geren] was. I played maybe once or twice a month against a lefty and get maybe one hit and then it just made me into [a player] that would only face righties."

DeJesus was out of new manager Bob Melvin's lineup against Royals lefties Danny Duffy and Jeff Francis in this series. This season, DeJesus is batting just .125 (5-for-56) against left-handed pitchers and .274 (43-for-157) against right-handers. His career splits are much better -- .267 against lefties, .295 vs. righties.

"I've just got to keep working. I'm not going to stop doing my whole routine," he said.

DeJesus is eligible for free agency after this season.

"So whatever happens, happens," he said. "All I can do is come here and be positive. What else am I going to do? Be mad about it? It'd just make it worse."

Crown points

• Sean O'Sullivan's ailing right biceps felt fine after he threw a 48-pitch bullpen session on Wednesday. He expects to throw a simulated game on Saturday in St. Louis and then be ready for a Minor League rehabilitation assignment.

• Pitcher Kevin Pucetas, after clearing waivers, is back with Triple-A Omaha. He was designated for assignment Friday to make room on the 40-man roster for third baseman Mike Moustakas.

• Left fielder Alex Gordon got a break from the starting lineup on Thursday, and Mitch Maier took his spot in the field and at the top of the batting order.

• Latest figures from the Elias Sports Bureau list the Royals as the youngest team in the Majors by nearly a year and a half, averaging 26 years, 152 days, to second-place Florida's 27 years, 327 days.