SURPRISE, Ariz. -- Zack Greinke knows he has to perform well in Spring Training to earn a spot on the Royals' 12-man staff or he could be opening the season in Omaha.

Greinke had his best outing so far on Wednesday, tossing four scoreless innings in the Royals' 6-2 victory over the Rockies. Greinke struck out six of the 15 batters he faced, walked none and yielded four hits.

There may be just one spot open in the rotation, and Brian Bannister and Joakim Soria have been impressive in their early March auditions.

"Zack didn't harm his chances by any means," Royals manager Buddy Bell said. "Now is the time when these guys have to start showing some things. They should have their stuff by now, have their feet underneath them. We're not ready to make any kind of decisions. He is certainly in the thick of things. It is time when guys have to really step up, and he did today. It was nice to see."

Greinke lowered his ERA from 7.20 to 4.00.

"I just needed an outing to do good, just so they could see it," Greinke said. "I felt like I've thrown good the times before, but just the results weren't there. So I was like, 'If I do the same thing or a little better, then it will be about time to even out to where an outing will go my way instead of not.'"

Greinke is enjoying the competition to fill the vacancy for the fifth slot in the rotation.

"I like what is going on because we have like eight people who can do the job," Greinke said. "That is what we haven't had in the past. When someone didn't work out, there was no one really to fill in. This year, we have a lot of people that can come and do the job. That is what I like.

"Even if I don't make the team, if someone doesn't do the job they'll bring someone to fill in. If I do make the team, then if I don't do the job they have someone to come and fill in to help the team win right away. That is one thing that's really going good for our club this year, for our pitching staff. We have a lot more options than in the past."

Spring Training
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Pitcher ailing: Bell said left-hander John Bale would not pitch in the next week to 10 days and "could be" a candidate to open the season on the disabled list.

"We're still hoping he'll be ready, but it's going to be awfully close," Bell said.

The Royals have sent an MRI of Bale's sore left arm and upper back to team physician Dr. Steve Joyce in Kansas City.

Also, outfielder Shane Costa remains sidelined with a strained back, which he said he did swinging in a game.

Hudson throws: Luke Hudson tossed five shutout innings in a Minor League game for Triple-A Omaha against Double-A Wichita. He gave up five hits, walked one and struck out four.

"At 10 o'clock in the morning, it is tough to get going," Hudson said. "I felt better as I went on. It's a different setting. We just get our work in, get the pitch count up and get the arm strength. It's the same thing, but no crowd.

"It is not difficult to get the adrenaline flowing. It comes natural. Once the hitter is in the box, you don't want to take it easy or coast because that is when you get your fanny kicked."

Hudson, who is penciled in as the No. 3 starter, said he worked on his curveball, throwing more than he normally does.

"I don't try to analyze it too much. I just go out there and get the work in that I need to get done, and [focus on] being able to execute the pitches and refining everything," Hudson said.

Hochevar struck: Luke Hochevar, the first-overall pick in the 2006 First-Year Player Draft, was removed from a Minor League game on Thursday after being hit in the left shin by a batted ball.

Hochevar said he was fine after having it taped up.

Elarton's progress: Scott Elarton was pain free on Wednesday after throwing 25 pitches in batting practice on Tuesday to five Minor Leaguers. It was Elarton's first time to face hitters since last July. He had shoulder surgery in August.

"It went very well," Elarton said. "Physically, it felt really good. I was actually surprised how I had command of the ball. The main thing right now is I had no soreness [the day after]. It is how I recover."

Elarton is scheduled to throw a 35-pitch batting practice session on Friday. After four BP sessions, if he has no setbacks, he will pitch one inning in a Spring Training game and then remain in Arizona to continue to increase his pitch count.

"Once I get to 80-90 pitches in a game, I'll feel like I'm ready," he said.

He is not ruling out returning to the KC rotation in May.

"I'm just trying to stay patient. That is really the hardest part right now because it's feeling so good. I want to push it, but that is really not smart. I'll just keep taking it slow and I'll be better off in the long run if I do."

On deck: Royals left-hander Jorge De La Rosa and Giants southpaw Barry Zito are slated as the pitching probables when the two teams pair up on Thursday for a 3:05 p.m. CT start at Surprise Stadium.