Matusz, the fourth overall pick by the O's in the 2008 draft, hasn't pitched in the big leagues since losing a fourth straight start back on June 30 to St. Louis. After going 10-12 a year ago, Matusz's 2011 season was delayed by injury and he was just 1-4 upon his return and pitched to an 8.77 earned run average.
"I've been able to get in a nice, consistent groove and feel confidence about all my pitches and have a good idea of what I'm doing out there," said Matusz, who tossed a shutout in his last Triple-A start for Norfolk. "I'm really looking forward going into my start tomorrow, especially coming off a bunch of good outings down there, and being able to keep my groove going."
Matusz's lone win this season came against the A's and he is 2-2 in four starts against them with a 5.48 ERA.
Oakland, meanwhile, will counter with righty Guillermo Moscoso, who is 5-6 with a 3.52 ERA. Moscoso won for the second time in three starts on Thursday in Toronto, as he allowed two runs (one earned) and three hits in six innings.
Moscoso lost to the Orioles back on June 7 and is 1-1 in four games (two starts) against them with a 6.94 ERA.
Baltimore drew first blood in this set on Monday, as Robert Andino hit the go- ahead two-run double in a four-run seventh inning, helping the Orioles to a 6-2 win. Josh Bell added a two-run hit in the deciding frame and Mark Reynolds homered for Baltimore, which has won two in a row following a three-game slide.
Tommy Hunter (2-2) allowed 10 hits and two runs over 6 2/3 innings for the win.
"I like throwing here. There's a lot of foul ground. It's a big factor," Hunter said. "It's a big ballpark at night, too. It just works well with me."
Gio Gonzalez (9-11) was tagged in the loss for four hits and four runs with three walks in six-plus frames.
The O's have won four of their seven matchups with the A's this season after dropping seven of the 10 matchups in the season series a year ago.