BALTIMORE -- Brian Roberts hasn't played a Major League game in more than a year, but Tuesday could finally put an end to that stretch.

Roberts is scheduled to end his 20-day rehab stint on Monday after a long battle with concussion symptoms.

If there are no setbacks, it is expected that Roberts will be activated from the 60-day disabled list and be available to the Orioles on Tuesday.

Roberts went 0-for-4 on Sunday in what was likely his last Minor League game before meeting with the Major League club during its Monday off-day.

Manager Buck Showalter was noncommittal about Roberts' immediate future.

"I don't know, we'll see," Showalter said. "As far as where he's playing and what position he's hitting and all that stuff, I haven't made that lineup out yet."

In 13 Minor League games spread between Class A Delmarva, Double-A Bowie and Triple-A Norfolk, Roberts has hit .238 with a home run and four RBIs.

Showalter was also hesitant to discuss what Roberts' return would mean for Robert Andino, who has filled in for Roberts at second base to start the 2012 season.

"There's some good options," Showalter said. "Robert has been a guy I've always felt comfortable playing anywhere."

Showalter even mentioned the outfield as a possibility for Andino, although he has played there only sparingly to this point in his career.

"I think Robert would be an above-average defender everywhere in the infield," Showalter said.

The Orioles will need to make a spot on both the 25- and 40-man rosters if Roberts returns, which could mean the end of Steve Tolleson's time in Baltimore.

Tolleson started at third base Sunday and delivered the game-tying three-run home run in the fourth before making a diving stop in the sixth that got starter Jason Hammel through his final inning.

"I knew that I was up here on borrowed time," Tolleson said. "I don't know if that's going to be the end of it. [I'm] very excited to have Brian Roberts back on this team, whether it means I'm going to Triple-A or whatever. Roberts is irreplaceable on this team, and we're excited to have him come back."

"Obviously, we're hoping that Robby joins us Tuesday," Showalter said. "We'll have a decision to make, and unlike years past, we'll be sending some people out that we'd like to keep."

O's weighing options for Saturday's starter

BALTIMORE -- The Orioles have been getting by with a four-man rotation for about two weeks, but on Saturday, the team will again be in need of a fifth starter.

Manager Buck Showalter has plenty of options to choose from.

Reliever Dana Eveland, recently signed veteran Jamie Moyer, Triple-A standout Chris Tillman, freshly assigned Miguel Gonzalez, recovering starter Zach Britton and even Jake Arrieta, who was moved to the bullpen on Saturday, are legitimate possibilities.

"We'll see," Showalter said. "We've got some depth to pick from there, if we have a need. I hope we don't have a need. Obviously we're going to need a fifth starter."

Eveland and Gonzalez, who have both performed well in long-relief roles with the Orioles, were considered for last Saturday's start but were needed out of the 'pen leading up to the weekend. Tommy Hunter was ultimately named the starter and allowed three runs in seven innings.

Tillman has posted a 4.01 ERA in 67 1/3 innings with Norfolk, and a Saturday start would come after four days rest on his current schedule.

Britton could be ready to make his return from a left shoulder impingement that has kept him on the disabled list since March. After allowing four runs on seven hits in six innings during his first start at Norfolk on June 5, he gave up three on seven hits while lasting just 4 2/3 on Sunday.

Moyer, a 49-year-old left-hander who was signed to a Minor League contract on Wednesday, threw five shutout innings in his debut with Norfolk on Saturday. He allowed only one hit and didn't walk a batter while striking out five.

Showalter said Moyer's outing could have been even stronger were it not for a pair of fielding errors made behind him, but the skipper did not offer any comment on what the start means for his future with the team.

Executive vice president of baseball operations Dan Duquette has said that Moyer's time with Norfolk is considered an audition for the Major League club.

Worth noting

• Jake Arrieta was available to pitch out of the bullpen on Sunday, manager Buck Showalter said prior to the 5-4 win in 10 innings over the Phillies. Amid rampant speculation that Arrieta would be sent down to Triple-A Norfolk on Saturday to make room for Tommy Hunter, the O's instead chose to option reliever Miguel Gonzalez and move Arrieta to the bullpen. Arrieta last pitched on Friday, giving up career highs of nine runs and 11 hits in just four innings against the Phillies.