MINNEAPOLIS -- Koji Uehara rejoined the Orioles in Minnesota on Thursday and pitched in right away, tossing a perfect eighth inning in a 2-0 win over the Twins.

"What he has one time around, he has deception," Trembley said. "He'll use different arm angles, and he'll take something off. Boy, it's nice to have him out there. It was a big lift for our team."

Koji tossed nine of his 12 pitches for strikes and was pleased with where he was at.

"The pitchers and position players, they told me, 'Welcome back," he said through interpreter Jiwon Bang. "It felt really good."

Koji figures to get most of his time in the seventh or eighth inning, although Trembley said he would not rule out using the Japanese reliever in the ninth if current closer Alfredo Simon is not available.

Koji figures to get most of his time in the seventh or eighth innings, although Trembley said he would not rule out using the Japanese reliever in the ninth if current interim Alfredo Simon is not available.

"I probably wouldn't do that [Thursday] with Koji," Trembley said. "But if Simon has pitched a couple of days in a row, I would. But we've got to get to that point first, and I'm expecting that we will."

Koji was placed on the 15-day disabled list with a left hamstring strain on April 3 (retroactive to March 26), and after a pair of appearances at the team's Double-A and Triple-A affiliates, he was officially reinstated Thursday morning.

"I'm very, very happy to be here," he said. "I'll just prepare myself to be ready and throw wherever they want me to throw."

While Koji's hamstring is now 100 percent, he acknowledged the injury will still be in the back of his mind when he takes the mound. Uehara has a long history of hamstring issues, dating back to his playing days in Japan, and he made just 12 starts last year in his first season with the O's.

Koji pitched to a 1.69 ERA in six Spring Training games before exiting in the fifth inning of March 18's contest after he felt his left hamstring tighten up.

The Orioles hope limiting Koji to a one-inning role in the bullpen will help keep him healthy and productive. Baltimore is still missing regular closer Mike Gonzalez (strained left shoulder), who began a throwing program last week in Sarasota, Fla., but has not yet thrown off a mound. If there are not setbacks in Gonzalez's program, he could be activated by early June.

Bullpen transition has suited Berken

MINNESOTA -- A starter his entire career, Orioles reliever Jason Berken admits he didn't know what to expect when he made his first Opening Day roster as a long man out of the bullpen.

"I feel like I've been able to transition pretty good with a lot of help from guys who have been in the 'pen [to] help me smooth it out," Berken said. "I like coming to the field every day knowing I have a chance to pitch."

Over his first seven appearances as a reliever, Berken has posted a 1.88 ERA, allowing three earned runs over 14 1/3 innings. Entering Thursday, the right-hander had allowed just one earned run over his past six appearances and was holding left-handed hitters to a .083 (2-for-24) average, second in the American League only to Texas' Neftali Feliz (.080). Right-handed hitters were batting .393 (11-for-28) off Berken.

"I've been able to sink my ball away to lefties," Berken said. "The biggest thing is I've been able to throw my two-seamer behind in the count, that's kind of helped me along the way. Whatever I'm doing now, hopefully I can keep doing it and do a little better against righties as well."

After making 24 starts for the O's last season, Berken is also learning to adopt a slightly different approach in the bullpen. While talking with fellow reliever Matt Albers about whether to throw a curveball to certain hitters, Berken said Albers told him, 'If you're going to get beat, you might as well get beat with your best stuff.'"

"As a starter, you throw every pitch," Berken said. "But for me, coming in now knowing I'm only going to face a guy potentially once. You want to go at him with your best stuff."

Mark Hendrickson, the Orioles' other long man, said moving Berken to the bullpen has allowed the young righty to become less analytical.

"He's more reacting because he doesn't want to waste a pitch," Hendrickson said. "He gets in there, the adrenaline's flowing, just allows himself to pitch. And that's what works for him, which is good."

"Because ultimately, it's about adjusting to the 'pen and saying, 'OK, what's going to allow me to be successful?' And he's done that very well so far."