KANSAS CITY -- Right-hander Roman Colon was a big part of the Royals' bullpen in 2009, pitching in 43 games that season. Now he's back, called up from Triple-A Omaha to bolster a depleted relief corps.

To clear a roster spot on Thursday, the Royals optioned first baseman and designated hitter Clint Robinson back to Omaha.

"I didn't feel like I went away. This is home for me. And the Kansas City Royals have been showing that a lot to me. Here I am again, and I'm trying to make it happen again," Colon said.

After starting the 2010 season with Kansas City, he was quickly optioned to Omaha and decided to try baseball in Korea. He spent most of that year with the KIA Tigers and had an 8-7 record. But he returned to the United States last year and pitched for the Dodgers' Triple-A club at Albuquerque. This year, he signed back with the Royals' organization.

"I went to Korea, pitched over there a little bit. I didn't regret going there. I experienced a lot of things," he said. "I learned a lot from the Korean people because they have a pretty good culture."

For Omaha this year, Colon was 3-1 with five saves and a 3.34 ERA in 21 games.

Robinson was brought up as an extra bench player with Interleague Play at National League cities coming up in nine of 12 games. The Royals have six more of those games coming up at St. Louis and Houston in the coming road trip. So why bring in another pitcher?

"Have you seen our games lately?" manager Ned Yost said. "I've burnt the bullpen up to a crisp in the last two days."

With the bullpen used for nine innings in the first two games of the Milwaukee series, Yost wanted another arm, preferably right-handed against the predominantly right-handed Brewers lineup. Louis Coleman had been optioned the previous day when starter Jonathan Sanchez was activated and couldn't return for 10 days. Therefore, Colon was tapped.

"We just needed another arm," Yost said. "We told Colon we don't know how long it's going to be -- it could be for a day, two days or three days. We've got to get our bullpen back in good shape before we make another move."

While the Royals could drop a pitcher to add another hitter for the series at St. Louis, it won't be Robinson because he can't be recalled for 10 days. So infielder Irving Falu or outfielder David Lough could be in line if that happens.

Robinson was used four times as a pinch-hitter and went hitless with two strikeouts.

"It was tough," Yost said. "Every situation I put him in was against closers or seventh- or eighth-inning guys so it was really difficult -- not for just a young guy but for a polished pinch-hitter in general. Having those types of at-bats is very tough but I thought Clint did a good job. It would've been a different story if we didn't have the necessity."