Aaron Harang in Mariners' rotation

SEATTLE -- All manager Eric Wedge needed to see was a brief bullpen session from Aaron Harang to slide him right into the Seattle Mariners' rotation and move Blake Beavan to the bullpen.

Only 11 games into the season, the Mariners made a significant change Friday, a day after Harang was acquired in a trade with Colorado. He will make his first start for Seattle on Tuesday night against Detroit.

"He's a veteran guy. He knows what he needs to do to go out there and be successful," Wedge said. "He has a great feel for himself. He's had a tremendous amount of success at the big league level. And again, he had 31 starts last year and had a pretty good year."

Harang threw a 40-pitch bullpen session for Mariners coaches on Friday afternoon, before Wedge announced a decision. The move was not a surprise; Harang has pitched out of the bullpen only six times in his career and Beavan struggled badly in both of his starts this season.

The trade ended a week of speculation about where Harang's career was headed after he was traded from the Los Angeles Dodgers to Colorado and designated for assignment by the Rockies.

The Rockies acquired Harang last Saturday when they traded catcher Ramon Hernandez to the Dodgers. The right-hander went 10-10 with a 3.61 ERA last season for the Dodgers, but was left out of their crowded rotation this year.

Harang, who turns 35 next month, is 105-104 with a 4.19 ERA in 11 major league seasons with Oakland, Cincinnati, San Diego and Los Angeles.

Colorado never intended to keep Harang, and the Mariners needed another starter after allowing Jon Garland to opt out of his contract this spring rather than adding him to their roster. The Rockies scooped up Garland and put him in their rotation.

Harang said he got a call shortly after the trade between the Dodgers and Rockies went through and was told Colorado would quickly look to deal him. Harang spent his time in limbo at home in San Diego throwing as much as he could. He tossed five innings in a simulated game this week against batters.

"It was a little never-racking, biting your nails a little bit," Harang said. "But it was good. I got to spend some time with my family before I took off and try and do what I could working out and throwing, making sure I was ready to go."

Harang immediately gives Seattle some experience and depth on a pitching staff that's been beaten up early in the season, especially the back end of the rotation. Rookie starter Brandon Maurer didn't make it out of the first inning Tuesday night and Beavan has allowed five earned runs in both of his starts.

Beavan's move to the bullpen gives Seattle the long reliever it has lacked early this season.

"He's still a young pitcher figuring it out and still needs to improve," Wedge said. "Sometimes when you move somebody to the bullpen it is a different look, it is a different feel. ... Maybe that helps him along, too."