To make room on the 40-man roster for Rodriguez, left-handed pitcher Justin Marks was designated for assignment.
Rodriguez, 24, was signed as a Minor League free agent last winter after seven seasons in the Tampa Bay organization. He began the season with Double-A Northwest Arkansas, giving up two earned runs and 11 hits in 11 innings with 12 strikeouts and four walks. Promoted to Omaha, he'd made just two one-inning scoreless outings last Tuesday and Wednesday.
"He's a kid that has a power arm. He's 95 to 100 miles an hour, good breaking ball. He's had some issues with his shoulder, but he's completely healthy now," manager Ned Yost said. "We'll take a look at him. He's throwing the ball good now."
A Venezuela native, Rodriguez had shoulder surgery in October 2010. In his eight seasons in the Minors, he has a 10-27 record and a 3.80 ERA in 101 games (64 starts). This is the first year that he's played above the Class A level.
Coleman pitched 17 times in relief for the Royals and had a 1-0 record, a 6.27 ERA and opponents were hitting .316 against him.
"Louie Coleman is a real important part of our 'pen," Yost said. "He's a guy we look to match up with [Kelvin] Herrera, [Aaron] Crow, [Tim] Collins -- we need all four of those guys to be producing and Louie just wasn't. He kind of got relegated to a mop-up role and we can't have that. He's too good for that. So we wanted to send him down and get his slider going again and get him to command his fastball again and go from there."
Coleman had a setback early in Spring Training when the middle finger of his pitching hand was struck by a ball. It was sore and swollen and he began the season on the disabled list, rejoining the club April 9.
"He just hasn't gotten going yet," Yost said. "The thought is to get him down there, get him pitching more consistently. He did it last year. He wasn't real sharp. We sent him down and when he came back, he was lights-out, really. The hope is we can do it again -- get him down there, get him back quick."
Marks had a 3-2 record and a 5.64 ERA in 13 games (two starts) for Omaha.