As the Orioles open their Grapefruit League schedule Monday with a day-night, split-squad doubleheader, expect manager Buck Showalter to examine all of his potential leadoff hitter options with Brian Roberts' health still uncertain.

"We'll move some things around, look at some different scenarios," Showalter said Sunday. "You'll see a number of guys there. I want to take a look at how it feels and how it looks. If we're comparing all of them to Brian Roberts, they're all going to finish second."

Showalter has plenty of options.

Leftfielder Nolan Reimold, whose .328 on-base percentage was tied for second-highest among starters, is a front runner. Showalter said he'd consider J.J. Hardy, but he seems to be an unlikely candidate. Robert Andino is another option, but he could fit better at the bottom of the order. Even newcomer Wilson Betemit, who has a career .406 batting average in limited at bats at the leadoff position, is a possibility.

"We've got some guys who we've looked at what they've brought in the past that are interesting," Showalter said. "It may not be a guy who looks like Brian, and brings the things that he brings. We know it won't be, but I'm OK with our options. You're assured of hitting leadoff one time. It's more about who's behind who and the way it presents the most challenges for the opposing pitcher."

Trust that Showalter will spend plenty of time tinkering with his batting order over the next month.

"I actually think (choosing) the four hole is going to be more challenging than the one hole to figure out," Showalter said. "There are certain things that guy's more assured of than anyone else."

Britton progressing

Left-hander Zach Britton, who is rehabbing from left shoulder inflammation, had his second bullpen session moved up one day to Sunday, throwing about 30 pitches off a full mound. Originally he was slated to have two days off after his first session Friday and throw again Monday.

"I think it was a lot better than the first one," Britton said. "I felt more comfortable on the mound today. I was able to make adjustments a lot quicker, too, and I was throwing a little bit harder, my tempo was a little better."

Britton is slated to throw another bullpen on Tuesday, throw a live batting practice session late this week and said he expected to pitch in a game situation by this time next week.

As for regaining the feel of his pitches, he's thrown some sliders, change ups and curveballs.

"Obviously, my command can get a little better, but it's my second bullpen, so I'm not putting those expectations on myself right now," he said. "The next one, I'll try to evaluate a little more from a command standpoint, try to hit some corners and do some different things."

Chen dealing with adjustments

Taiwanese left-hander Wei-Yin Chen, who struggled in his intrasquad game outing Saturday, said he's still getting adjusted to different mounds than the ones he has been used to pitching on in Japan.

"I feel like it's a little bit flat over there (in Japan), so I'm still making an adjustment," Chen said through interpreter Tim Lin. "It feels fine to me, but I'm trying to fit in and get adjusted to it."

Chen faced five batters and threw 31 pitches before the inning was ended because of a pitch count, allowing two hits, one walk with one strikeout.

Showalter said the conditions, which included a wind blowing out to left, might have contributed to Chen's struggles.

"I think some of the challenge Chen had yesterday, if you keep in mind that most of their games are played inside, I don't know if he ever pitched in those conditions," Showalter said.