DUNEDIN, Fla. -- Orioles reliever Matt Lindstrom threw a lighter 30-pitch bullpen session on Monday morning, and afterward the right-hander reported no pain in his lower back, an issue which crept up on him Thursday morning.

"My arm feels great," said Lindstrom, who last pitched in a game on Wednesday. "I'm just working on my stuff, all three pitches. I look forward to getting back on the mound and getting myself ready for the season."

Lindstrom isn't sure exactly what caused the back spasms, but he thinks his bed -- which he has replaced -- was a contributor. The right-hander played catch on Sunday and has been getting treatment to help calm things down. Assuming Lindstrom comes in Tuesday feeling OK, he will be eligible to get back into games immediately. Pitching coach Rick Adair said Lindstrom could throw Tuesday or Wednesday.

Acquired in an offseason trade with Colorado, Lindstrom is expected to be one of the Orioles' late-inning arms in the bullpen.

Showalter pleased with Chen's progress

DUNEDIN, Fla. -- From the get-go, Orioles manager Buck Showalter thought about having new Taiwanese pitcher Wei-Yin Chen stay in Sarasota, Fla., and make his second spring start in an unofficial simulated game instead of a road contest against Toronto. But then Showalter thought better of it.

"I think it's more important with his development, just everything that he can get exposed to that he's going to be challenged with," Showalter said of Chen, who allowed one run over three innings in Dunedin on Monday. "[I'm] just trying to keep all that in mind. And so far, so good. I'm pleased with him."

Chen, who had been pitching in Japan before signing a three-year deal with the Orioles this winter, is still adapting to his new country, teammates and Major League Baseball's rules. Asked if he felt acclimated to the shorter rest in between starts, Chen said it's still too early in spring.

"I don't know yet, because I only pitched two innings before this," Chen said through interpreter Tim Lin. "I don't know the feeling of a real game yet. It's still baseball. It's still the same game for me."

Chen worked deep counts on Monday, but he said he was pleased with his overall performance. The 26-year-old lefty allowed two hits and a walk to go along with two strikeouts over the 52-pitch outing. Showalter is well aware of the acclimation period and is confident Chen -- who was consistently clocked in the high-80s on Monday -- will continue to make strides before heading north.

"Every pitcher goes through periods," Showalter said. "[Francisco] Cordero is throwing 88-89 [mph], [but] it ain't going to happen when the bell rings. It's a process. Just keep in mind where the finish line is."

Orioles mum on Opening Day starter

DUNEDIN, Fla. -- With just over three weeks until the Orioles break camp, manager Buck Showalter said the team's Opening Day starter is not a topic of conversation within the organization "at all" as Baltimore tries to sift through a large volume of arms in camp.

"Because we haven't [announced it], it kind of tells you why," Showalter said of his club, which has depth but lacks any established front-line starters. "We've got a number of candidates that are going [to be in the mix] to pitch the first game of the season. We don't look at it as the Opening Day No. 1. We look at it as, 'OK, here's the guy who's going to pitch first.'"

The offseason trade of Jeremy Guthrie -- who was the O's Opening Day starter three of the last four seasons -- and the struggles of the organization's young arms leaves a wide-open race for who will take the hill in Baltimore on April 6. Showalter said he has "two or three" names in his head, with one being a wild card, and it's fair to speculate that Jake Arrieta -- who started last year's home opener -- is in the mix along with Tommy Hunter and Jason Hammel.

"I don't spend much time on it," Showalter said. "I don't have to yet. Let them pitch. It's about things other than pitching, too. There's a reason why we started Jake in our home opener last year. We wanted to get him as much time as possible [this spring in coming off elbow surgery]. We wanted to pitch him fifth. There's some other issues to take into consideration."

Tidbits

• Tommy Hunter (lower back) came through three innings in a "B" game on Sunday with no problems, and he will pitch four innings Friday in either a Minor League game or the Orioles' game.

• Zach Britton's next step will be two innings in a Minor League game on Thursday. Britton, who threw one inning in Sunday's "B" game, will throw a light side session on Tuesday.

• Reliever Jim Johnson will make his spring debut in Wednesday's game against the Pirates.

• Nolan Reimold continues to improve after taking a ball to the left cheek, and the swelling is down considerably. He will see a dentist Monday and play in Tuesday's game.

• Ronny Paulino will probably serve as the designated hitter in Tuesday's game, according to manager Buck Showalter. Paulino was in the clubhouse Monday morning and said he had been working out while waiting for his visa issues to be resolved. He said the biggest challenge now is learning all the team's pitchers.

• Troy Patton has been dealing some arm fatigue, and the team backed off him for a few days. Patton will throw in Tuesday's game.

• Taylor Teagarden (lower back) had an MRI on Monday morning. Teagarden already had an X-ray, and Showalter said the latest test is really just for piece of mind and to make sure there's no damage. The X-rays showed no structural damage, but an MRI can show more than an X-ray can.

• Tsuyoshi Wada will throw in a simulated game on Wednesday. Assuming all goes well, he will get into a game Sunday or March 19.

• The Orioles will have several players pitch in a Minor League Class A game at Twin Lakes Park on the March 19 off-day. The Triple-A and Double-A squads are on the road.