PEORIA, Ariz. -- A move that was so inevitable a week ago that even Brandon Morrow realized it, the Mariners have decided to move the right-hander from the rotation back to the bullpen.

Morrow began Spring Training as a strong starting candidate, but various ailments, including the flu and soreness in his right forearm, prevented him from throwing the amount of pitches that he needed to build his arm strength.

And so, after comparing the pros and cons of both jobs, the 24-year-old decided on his own that pitching out of the bullpen is best for him and the team.

"I went to them," he said on Sunday morning at the Peoria Sports Complex. "They were going to give me every chance to start because that's what I've asked for in the past. But I decided about a week ago that I'm better off, and I can help the team more, in the bullpen."

Manager Don Wakamatsu said Morrow would become "a bullpen piece and we'll see where it slots out. We think we can get three more outings from him before Spring Training ends. Then we'll evaluate and make a decision, probably in Las Vegas."

The plan is for Morrow to pitch in back-to-back games on Tuesday and Wednesday. If he passes that test, he would then throw one more time in Las Vegas for his final appearance before the Mariners' regular-season opener against the Twins on April 6.

The Mariners bullpen has been in flux the entire spring and figures to go down to the final day before the seven relievers are selected for the 25-man Opening Day roster. The list of candidates was reduced by one on Sunday when right-hander Tyler Walker was released.

Morrow presumably would move into the closer role at some point.

He finished second on the staff last season with 10 saves and has the stuff to be one of the best door-slammers in the Major Leagues.

Morrow said his decision had more to do with him being better suited for the bullpen than the closer role still being wide open.

"The way I pitch, and the way my body is, I'm better on a low-inning, day-to-day basis," he said. "Diabetes is a little bit of a factor, but the major thing is the excitement from coming in at the end of the game. Once you get a taste of closing, I don't think many people would want to go back to anything else."

Morrow, the Mariners' first-round Draft choice in 2006, was used as a starter and reliever during his college career at the University of California-Berkeley. He started five times in eight Minor League games in '06 and pitched so well during the following Spring Training that he earned a spot in the Mariners bullpen.

The high-powered Bay Area native appeared in 60 regular-season games that season, posting a 3-4 record and 4.12 ERA. After missing a big chunk of Spring Training because of shoulder discomfort, he started last season in the Minors, rejoined the Mariners on April 17, and made 45 relief appearances before being sent to Triple-A Tacoma to be made into a starter.

He made five starts for the Mariners and went into the offseason as a virtual lock to open the '09 season in the rotation.

The closer role became vacant in December, when right-hander J.J. Putz was traded to the Mets, but the Mariners stuck with their plans to keep Morrow in the rotation, which he had requested.

"I've been wrestling with it since the trade of J.J.," Morrow said. "There were a lot of rumors early on that I was going back to the bullpen. But out of respect for me, the front office [kept him in the rotation]."

He reported to camp prepared to continue being a starter, but it was becoming increasingly evident that he would not be game-ready when the season started.

"It was a tough decision," he said. "I went in with a lot of pros and cons and why I would do one over the other. I think everybody agreed that I would be best suited as a reliever and that would help the team the most.

"It just came down to [me thinking] I'd be better out of the bullpen."

That being said, he doesn't expect to start the season in the closer role.

"They're not just going to hand the job over to me without me showing that I can come back and be the same type of reliever I was last year," he said. "I think we'll probably go with the hot hand for a little bit and somebody will step up and take over."

The smart money says that eventually will be Brandon Morrow.