BALTIMORE -- Orioles top pitching prospect Dylan Bundy will head to instructional league when his season with Double-A Bowie ends, manager Buck Showalter announced prior to Wednesday's game.

The news effectively eliminates speculation that the 19-year-old Bundy would be a September callup as part of Baltimore's playoff push.

Bundy pitched 5 1/3 innings on Tuesday night, allowing a pair of runs and walking four, and the organization doesn't feel he's ready right now. Since being promoted to Bowie, Bundy -- in his first professional season -- is 2-0 with a 3.24 ERA over 16 2/3 innings, allowing 14 hits (three homers), three hit batsmen and eight walks against 19 strikeouts.

"Instructional league starts on the 12th [of September]," Showalter said. "There's some things, he's at a level where he's been challenged, just like he got challenged more in [High A] Frederick. He had some outings that weren't [good]. I think the progression of his development has been great. Couldn't ask for a better progression."

The organization's top pitching prospect -- and one of baseball's top up-and-coming arms -- Bundy didn't allow an earned run in 30 innings of Low-A ball, then had a 2.84 ERA in 12 starts with Frederick before being promoted to Bowie.

The organization has monitored his innings all season, initially wanting to keep him in the 125-130 range, although there's indications he could go beyond that marker in instructional league. Bundy has thrown 103 2/3 innings so far this season.

Asked if the organization could call up Bundy in September just to expose him to the atmosphere, Showalter said in a perfect world, perhaps.

"[Procedurally], there's some other things that happen if you do that," Showalter said. "Frankly, what you got to ask yourself is, does he have a chance to be on your club to start the season next year? And that kind of effects the way you look at it.

"Right now, I want him to pitch his butt off and help Bowie win an Eastern League Championship. That's where I want his mindset. And then when that's over, look forward to working on some weaknesses down in instructional league with some very good instructors."

The Orioles could still call up a player from Bowie, with right-handed pitcher Tommy Hunter the most logical candidate. Prospect Mike Wright, who the organization selected in the third round of last year's Draft, is also turning some heads.

Matusz starting to get the feel for relief pitching

BALTIMORE -- Asked if he liked pitching in relief more than he thought he would, lefty Brian Matusz was pretty clear.

"I like to pitch in the big leagues and help the team win," said Matusz, a converted starter recalled after seven weeks with Triple-A Norfolk. "It's definitely a different role. It's been an adjustment. But so far, I like having to be ready every day and knowing I have the possibility of being in every game."

Matusz had made two appearances prior to Wednesday's game against the White Sox since being promoted on Aug. 24 and the Orioles -- who had him make a handful of relief appearances for Norfolk first -- were hopeful that the 25-year-old's numbers against left-handed hitters would translate in the bullpen.

And while it's been a small sample size, the experiment is looking good so far. Matusz struck out the only batter he faced last Friday and tossed two scoreless innings following Chris Tillman on Tuesday night.

"In my first two appearances, I've been able to come out and just attack right out of the gates," said Matusz, who threw 19 of 24 pitches for strikes in his last outing. "That's kind of been my mindset -- to throw strikes and attack guys. Right now, being the only lefty in the 'pen, there's an opportunity I could be in there every day. So, obviously, throwing less pitches and being fresh is key."

The Orioles have made it no secret that they would like another lefty in the bullpen, and veteran Randy Wolf -- who is expected to sign with the team in the few days -- could be a possibility, as well as Triple-A reliever Zach Phillips.

"I'm glad [Matusz is] off to a good start with it," manager Buck Showalter said of the role. "Because it's a weapon and a piece we are going to need in September."

What about beyond that? Executive vice president of baseball operations Dan Duquettte has said the organization still views Matusz as a starter long term.

When asked about his future, the lefty said he's not focused on anything but this year.

"We are in a special spot right now, fighting for the playoffs," Matusz said. "And my focus is just to contribute and help the team any way I can. And worry about that later."

Seven prospects going to Arizona Fall League

BALTIMORE -- The Arizona Fall League rosters were announced on Wednesday and seven Orioles' prospects are including on the Mesa Solar Sox Roster.

Pitchers Michael Belfiore, Chris Petrini, Clay Schrader and Mike Wright; catcher Brian Ward; infielder Jonathan Schoop and outfielder LJ Hoes are listed with the Solar Sox, with one empty spot.

Orioles manager Buck Showalter said Manny Machado was slated to play in the AFL before being called up to the Major Leagues, and the organization will fill the spot at a later date.

Hoes and Avery, both in Triple-A, are considered strong candidates to join the O's as September callups.