SEATTLE -- Ready or not, Adam Loewen's in the big leagues. Baltimore's top pitching prospect joined the parent club for the first time on Tuesday, replacing friend and fellow prospect Hayden Penn, who underwent an appendectomy Monday night. Loewen came from Double-A Bowie, skipping the Triple-A level.

There's no doubt about the 22-year-old's stuff and top-shelf potential, but there is a question as to whether he's a finished product. That's why the Orioles have brought him along slowly, but Baltimore manager Sam Perlozzo said he was the organization's best option to step in on short notice.

"You'll all know at the same time I do. You won't have to ask me," Perlozzo said when asked if Loewen was ready. "We're here to take a look at some of these guys. We're going to need them sooner or later. Hopefully, it will be sooner than we expected and he'll be able to contribute."

Loewen, the fourth overall pick in the 2002 First-Year Player Draft, has made just eight starts against Double-A opponents, posting a 4-2 record and a 2.72 ERA. The southpaw has more strikeouts (55) than hits allowed (46), and the organizational plan was to let him split the year between Bowie and Triple-A Ottawa.

His contract dictates that he has to be on the Major League roster next year, because he signed a big-league contract when he was drafted and is currently pitching through his final option year. In other words, in order to send him down to the Minors next year, he'd have to be exposed to waivers -- where he'd almost certainly be selected by another organization.

Loewen is well aware of that arrangement, and he's thankful to be in the big leagues before that comes to pass. He'll likely pitch in relief on Tuesday and move into the rotation next Sunday.

"I wanted to make it on my own, not just because my contract said I had to be up here. I wanted to do it for myself," Loewen said in the hours before Tuesday's game. "I haven't been told anything, so I'm just going to play it by ear right now. Obviously, I'm totally excited to be here. I can't wait to get on the field and contribute as much as I can."

The prospect grew up in nearby Surrey, British Columbia, and he expected at least 22 friends and relatives to be at Tuesday's game. Loewen said his experience in the World Baseball Classic, during which he earned a win over Team USA, prepared him for his promotion and took a lot of the anxiety away.

"I think it's going to help a lot with my first big-league appearance, whether it's today, tomorrow or down the road," he said. "Having that game under my belt, it felt like that was my first big-league start. I got all those things out of the way. Now I know I can compete at this level. Hopefully, I can just take care of business there."

On the mend: Baltimore trainer Richie Bancells filled the media in on Penn's surgical procedure, and he said it went as well as could be expected. The right-hander had a laparoscopic surgery, which is less invasive than its alternative, and he is expected to miss up to a month of action.

Penn already is out of the hospital, and Bancells said Penn will fly with the team to California on Friday, where he'll stay for a week or 10 days. After that, he'll be checked out by the team's physicians, and if everything is OK, he'll proceed to the Minor League complex in Sarasota, Fla., where he'll work on his conditioning.

"We had our fingers crossed that he was going to be somebody that could plug a hole for us," Perlozzo said. "The good thing is he had the less invasive surgery and won't be out as long as he could've been.

"Maybe in a month, we'll have him back pitching again."

Perlozzo visited Penn in the hospital and drove him back to the team hotel, and the skipper said the 21-year-old is upset that he missed his opportunity to stick on the big-league roster.

"He was pretty frustrated. He was really down," Perlozzo said. "I really believe the kid felt like he was ready. I think he is just really upset he's missed his opportunity. I reassured him, 'Not to worry, you'll get one here before this year is out.' He's anxious to get going and to get back."

In other injury news, Brian Roberts is expected to rejoin the team on Wednesday. The second baseman has missed more than three weeks with a strained groin. Right-handed pitcher Daniel Cabrera threw from 90 feet on Tuesday and may be two weeks away from returning to the mound.

Condolences: Right fielder Jay Gibbons wasn't with the team Tuesday night after learning that his mother had passed away earlier in the day. The Orioles don't know if or when he'll need to leave the team to be with his family.

"Prayers are going out for Jay, and that seems to be the biggest concern now," Perlozzo said. "I think he's in the process of making arrangements for his mom. It will become clearer [on Wednesday] what exactly his plans are and when the funeral's going to take place."

Perlozzo said he spoke to Gibbons on Tuesday and told him to take his time.

"He was calling to tell me he'd be late, and I'm thinking, 'You don't have to be late. Do what you have to do,'" Perlozzo said. "He called back and said he wasn't going to make it today and he'd try to get in [Wednesday]. When the arrangements become clear, we'll have a better idea. I basically told him to do whatever he has to do and don't worry about anything else."

Quotable: "Niner tries so darn hard that it could work against him. He's such an intense guy, you figure you better get him out of there before one of us gets killed in the dugout." -- Perlozzo, talking about Jeff Conine, who's been in a bit of a slump in recent days

Coming up: The Orioles and Mariners will meet again Wednesday, and the third act of the four-game series will pit Kris Benson against Seattle's Jarrod Washburn. Benson pitched a complete game in his last outing, notching Baltimore's only complete game this season.