KANSAS CITY -- Shortstop-turned-pitcher Tony Pena Jr. was back with the Royals Wednesday, but just for the day.

Pena stopped by Kauffman Stadium on Wednesday to throw in the bullpen for manager Trey Hillman and pitching coach Bob McClure before heading home to the Dominican Republic.

Shortstop Pena became pitcher Pena shortly after the Royals designated him for assignment on July 16. The club had obtained Yuniesky Betancourt to play shortstop and the need for Pena was over. As a shortstop anyway.

"Whenever they told me they were going to designate me for assignment, Trey mentioned that I could have a future on the mound," Pena recalled. "But during all that movement, I really wasn't listening too well."

Over the next few days Pena talked to his agent and then told Royals general manager Dayton Moore he'd give pitching a try.

"At first I really didn't want to do it, but I talked to some people and talked to Dayton and he said to try it out for the next five weeks and see how everything went," Pena said.

Everything went very well. He started with the Rookie Surprise team for two games, pitched seven times for Class A Burlington and wound it up with one outing for Triple-A Omaha. His totals in the Minor Leagues: 10 games, 19 1/3 innings, 12 hits, five earned runs, six walks, 18 strikeouts, 2.33 ERA, 1-2 record.

"I used to pitch growing up -- pitched and played short. I think everyone does, so it's something that I had a feel for. But I always preferred short because I hated the running the pitchers had to do," he said.

Pena, during his three years with the Royals, gained fleeting notoriety on July 21, 2008, when he was pressed into pitching service for an inning in a 19-4 loss to the Tigers. He pitched a perfect inning and struck out Pudge Rodriguez.

But, since being the starting shortstop in 2007, his playing time and his batting average diminished. And now, at 28, he's exploring a new career.

"It's been going well so I'm about 75 percent committed. I'm going to the instructional league and keep working on everything and see how it goes," Pena said.

After a month in the instructional league in Surprise, Ariz., he'll play in the Dominican Winter League with Aguilas and might pitch there as well.

So far, Pena is throwing a sinker, a slider and a split.

"My ball always moved, even throwing from short, my ball sinks normally so it's something that comes natural. And my breaking ball's been coming around pretty good, too," he said.

Pena said his fastball topped out at 93 mph.

"Playing catch here with all the guys, I'd always mess around throwing pitches with [Zack] Greinke or [Alberto] Callaspo so I had a feel for it," he said.

His main concern was how his arm would react to all the throwing. But after three scoreless innings for Omaha in his season finale, his arm was pain-free just as it was throughout his pitching adventure.

As a long-time position player, Pena has a good perspective about the thought processes of hitters.

"I have an idea of what hitters try to do so I can mess with them," he said. "I've got that to my advantage."

So does Royals closer Joakim Soria have to worry about his job?

"Not yet," Pena said, laughing.