With left-handed reliever Troy Patton on the disabled list nursing a sprained right ankle, the Orioles called up Matusz, who was converted to a relief role 10 days ago, to be the sole lefty in the O's bullpen.
"I'm confident in his abilities, I don't know if it's going to play up here," Orioles manager Buck Showalter said. "We'll see. [There's] only one way to find out. They don't have a Four-A league. It's a need we obviously have, and Brian is our best option at this point."
Matusz made his first big league relief appearace in the seventh inning of Friday night's game against the Toronto Blue Jays, entering with runners on second and third and two outs. He struck out lefty Colby Rasmus looking to end the inning.
Matusz is the only left-hander in the pen after the Orioles designated J.C. Romero for assignment Friday in a flurry of moves that also included rookie untility man Ryan Flaherty being activated and right-hander Tommy Hunter being optioned to Double-A Bowie.
Matusz was sent to Triple-A Norfolk on July 1 after going 5-10 with a 5.41 ERA in 16 starts, made four relief appearances for the Tides. He allowed four earned runs on seven hits in his first two outings out of the bullpen (totalling four innings), but he threw back-to-back scoreless outings of one inning each on Tuesday and Wednesday.
"His last two outings have been real good," Showalter said. "We did back-to-backs with him. He had a day off [Thursday]. And we will see if it plays up here. I think he's looking forward to having a chance to make a contribution to our club in a role we need with Troy out. He's also a guy who can give you some length, but if he shows you he can do the job, you'd rather not burn him out for two or three days if you can help it."
Showalter said he'd like to keep Matusz limited to one-inning stints for now, especially considering he is the sole lefty.
Matusz said his transition has "happened so fast," but that he feels he's becoming adjusted to the new role.
"I didn't exactly put a timetable for myself," Matusz said. "It was just a matter of going down there and getting better and improving every day. Obviously, with the role change things were different, but [I had to] accept that and just keep getting better and focus on what I need to do to help the big league club. That's what it's all about."
Right-hander Jason Hammel threw a two-inning simulated game Friday afternoon, throwing roughly 40 pitches in his first action against live hitting since undergoing arthroscopic right knee surgery in mid-July.
Hammel said his mechanics and command were off, but his knee was pain-free.
"I was just looking to see if my knee was going to be a factor and that wasn't at all," Hammel said. "We'll see how it feels tomorrow after getting off the bump. It's as close to being in a game situation without being in a game situation."
If all goes well on Saturday, Hammel will likely throw another simulated game Monday, probably about 3 or 4 innings as the focus turns to increasing his pitch count. Hammel is still eyeing an early September return.
Hot-hitting Flaherty returns
The Orioles activated Flaherty from the disabled list (bacterial infection) before Friday's game and inserted him into the starting lineup immediately at second base.
Flaherty had gone on a nine-game minor league rehab assignment at Triple-A Norfolk. He was hitting .409 (9-for-22) over his last five games and started at five different positions for the Tides — first base, second base, third base, left field and right field.
Flaherty was hitless in his first three rehab games — a span of 12 at bats — partially because he said he lost 10 pounds in recovering from the infection.
"I started a little bit slow down there for the first three or four games," Flaherty said. "After that I got it going. I just want to try to take that back here and try to help this team win."