BALTIMORE -- Right-hander Frank Mata has been one of the Orioles' most steady relievers since making his Major League debut on May 26. He has pitched seven innings in seven appearances, giving up just one run, six hits and two walks while recording two strikeouts.

"Everybody's waiting for the rookie guy who got called up, everybody's waiting for him to get nervous in his first outings in the big leagues," Mata, a native of Venezuela, said. "I was a little nervous, but I was just concentrating on throwing the ball over the plate and getting outs."

The former closer for Triple-A Norfolk has provided consistency for a bullpen that sorely needs it. He has steadily gained more trust from interim manager Juan Samuel, who inserted him on Tuesday with the bases loaded in the sixth inning against the Yankees. The 26-year-old retired Alex Rodriguez on seven pitches.

"Coming in with that situation, with the bases loaded facing who he was facing, you kind of think twice," Samuel said. "Is he going to be able to handle it? But he came right after those guys, and he's done a fabulous job for us so far."

"No, I wasn't really nervous, I was just concentrating on getting the out," Mata said of facing A-Rod. "I just get a little excited when I throw two pitches inside and they didn't give me those pitches. I just say, 'Oh, I [have to] be more nasty now, because it's a 2-0 count.' " --Noah Rosenstein

Roberts to receive epidural injection

BALTIMORE -- Second baseman Brian Roberts will receive an epidural in his lower back on Friday in St. Petersburg after extensive tests on the area came back negative.

Roberts announced the news during a call-in segment of the Scott Garceau Show on Thursday, and Andy MacPhail, president of baseball operations, confirmed the plan via text message.

Roberts also said during the show that he hopes to get back into games at some point this year despite his lengthy list of setbacks. He has already had two epidural injections and is on the 60-day disabled list with a herniated disc in his lower back. He had been progressing well enough to start a schedule to get into extended spring games in Sarasota, Fla., but he was scratched from his initial contest with "unrelated back pain" and hasn't played since. --Brittany Ghiroli

Samuel embraces Interleague challenge

BALTIMORE -- Interim manager Juan Samuel is excited for Interleague Play to resume on Friday, and not just because the first series will be against his former team, the Mets.

Samuel is embracing the added challenges that Interleague Play will present, such as adjusting to double-switch scenarios and finding ways to use players who are primarily designated hitters, when the Orioles travel to San Francisco and San Diego next week.

"You have to get creative, make sure you keep everybody fresh, map out some scenarios ahead of time," Samuel said. "It's a task that we're looking forward to."

Under former manager Dave Trembley, the Orioles played one Interleague series in May, going 1-2 against the Nationals in Washington. Their all-time record against National League clubs is 102-130, and they are 9-13 all-time against the Mets. They took a home series, 2-1, from New York in 2009 and are 6-8 all-time against them at Camden Yards.

For Jeremy Guthrie, who is starting the first game of the Mets series on Friday, one of the best parts of Interleague Play is the chance to step up to the plate.

"I was never a very good hitter in high school and never hit in college," Guthrie said, "but it's enjoyable, still, to go up there as long as you're not facing a guy that's throwing over 95 [mph] and you feel like you're going to get [beaned]."

But he isn't as thrilled at the prospect of facing pitchers from the mound.

"It's a lose-lose," he said. "If you get him out, you're supposed to get him out. And if he gets a base hit, you look a little silly."

The Orioles' Interleague slate spans their next 15 games, including series against the Mets, Giants, Padres, Marlins and Nationals. --Noah Rosenstein

Worth noting

Injured closer Alfredo Simon threw 30 pitches off the mound as planned on Thursday at the team's Minor League complex in Sarasota, Fla. Interim manager Juan Samuel expects him to be ready for the team's West Coast road trip next week. --Noah Rosenstein