PHOENIX -- Mike McClendon was manning the bucket in center field one day during batting practice, while his Triple-A Nashville teammates shagged fly balls.

Most lobbed easy tosses to McClendon, stationed safely behind a screen, and he dropped baseballs one-by-one into the bucket.

One guy was firing fastballs. Tim Dillard was hard at work.

"He was letting it rip from down low," McClendon said. "That's my experience with it."

It was part of Dillard's transformation from a traditional overhand pitcher to a down-low, sidearm slinger. It was 2010, and the right-hander had only recently been approached in Spring Training by Brewers officials with the idea.

It was bold change. Dillard had already tasted life in the big leagues, and he owned a fastball that touched 95 mph. But he listened to the pitch from assistant GM Gord Ash and then-Brewers pitching coach Rick Peterson, and committed to the change.

It was probably the right call. Dillard, now 28 and out of Minor League options, has a very good chance to crack his first Opening Day roster.

Had he refused the change?

Who knows?

"I wouldn't be in this clubhouse if I were still throwing over the top," Dillard said. "Not to say I wouldn't be pitching, not that I wouldn't be good, but I wouldn't have filled a need [for the Brewers]. I would have been bypassed by the great young pitchers who were throwing over the top who had better stuff than me. I could have been 32 before I found that niche."

Or, he might not have found it at all.

"I'm getting more and more comfortable with it," Dillard said. "There's no going back over the top."

Major League Baseball is sprinkled with pitchers who have made the switch. Among them is Cleveland's Joe Smith, who made the change after he was cut from his college team, and will make his 300th Major League appearance this season.

Wisconsin native Pat Neshek, currently with the Orioles, dropped down after he was struck in the forearm in high school and couldn't lift his arm. Likewise, Royals non-roster hopeful Tommy Hottovy changed his mechanics after Tommy John elbow surgery in 2008, and briefly made it up to the Red Sox last season.

The D-backs have two slingers: Brad Ziegler from the right side and John Patterson from the left. Ziegler made the adjustment in 2007 -- like Dillard, to spark a fading career. But Paterson said his arm angle dropped naturally in college, and he liked the effect against left-handed hitters, so he stuck with it.

For Dillard, the sidearm delivery has become second-nature. All you have to do is watch him in the outfield during batting practice. Every time a ball comes his way, he slings it toward that bucket.

Gone are the 94-96-mph fastballs. Now, Dillard tops out around 88 mph, but gets better action on his breaking balls, and is particularly tough on right-handed hitters who think the baseball, out of Dillard's hand, is coming right at them.

"It definitely paid off for him," McClendon said. "He's the type of guy who has good feel for baseball. He's an athlete, that's for sure, and you have to be to change your arm slot that much. We're not talking about a little, minor adjustment. It tells you his dedication."

The next step, Dillard said, is becoming more consistent against left-handed hitters, who get a nice, long look at the ball when Dillard lets it go. The key, he said, is getting ahead of those hitters with strike one and opening up his breaking stuff.

Since his transformation, Dillard went 11-7 with a 4.51 ERA in 24 Triple-A starts in 2010, then split 2011 between Nashville and Milwaukee. He struck out 27 batters versus four walks in 24 Brewers appearances. He held right-handers to a .206 average.

"I loved what he did last year when he came up," Brewers manager Ron Roenicke said. "When he first came up, he made really good hitters look really bad, and I was impressed."

Dillard is also regarded as a character, which is nice if you're one of the guys laughing with him in the bullpen.

He's already gotten television time for impressions of the late broadcaster Harry Caray, and current ESPN analyst Tim Kurkjian. Dillard also does a mean Roenicke that he shared in a long, rollicking clubhouse meeting last week.

A reporter can't even finish asking about Dillard's personality before McClendon starts laughing. He basically answered the question.

"One of the most amazing guys we have in here," McClendon said. "I give him rides home sometime, and you always know it's going to be a quick trip if you have 'Dilly' with you."

The Brewers have two open bullpen spots. Dillard and left-hander Manny Parra are leading contenders, partly because both are out of options. If he doesn't make the Brewers' Opening Day roster, the Brewers would have to expose Dillard to waivers.

"Sometimes [being out of options] hurts players, sometimes it helps them," Roenicke said. "In his case it may help him, but to tell you the truth, with him, I don't really think about that. I like this guy. I think he's done enough to show that he belongs on that staff."

Dillard says he's not paying attention to the camp battle.

"This is my sixth spring, and there have been years where I come in saying, 'I have a chance!' And then I'm the first one sent down," Dillard said. "It's hard to worry about this stuff. If you're in this game and you're worrying about that stuff, man, it is easy to get distracted. I had to decide four or five years ago, I can't do that. It will drive you insane."

Dillard owns the third-longest tenure among current players in the organization, behind Corey Hart and Parra. Dillard moved up a spot over the winter when Prince Fielder signed with the Tigers.

"It's fun being in the same spot, knowing everybody," Dillard said. "It's been a great organization for me."

And if this doesn't work out?

"Maybe I'll wind up playing second base," Dillard said. "I've got the sidearm throw down."