SARASOTA, Fla. -- Koji Uehara will undergo an MRI either Wednesday or Thursday to rule out any other possibility on his left leg or lower back other than the left hamstring strain he was diagnosed with.

Uehara exited the Orioles' game on March 18 game against the Blue Jays with a left hamstring strain and hasn't thrown on the mound since suffering the injury. The right-hander said Monday that he expects to start the season on the disabled list, given that there are limited opportunities to throw before Opening Day on Tuesday.

Manager Dave Trembley has said previously that Uehara would have to be able to show he can throw by mid-week to avoid the DL. Prior to Wednesday's game, Trembley acknowledged that Uehara will not be on the team's Opening Day roster.

"I can't honestly say that he will break camp ready to go," Trembley said. "I think it's too late for that to happen."

A former starter, Uehara played light catch on Wednesday. The Japanese right-hander has no timetable for when he will get back up on the mound.

Roberts plays in third consecutive game

SARASOTA, Fla. -- Orioles second baseman Brian Roberts played in his third consecutive game Wednesday afternoon, an encouraging sign for manager Dave Trembley.

"What he's trying to do is get in baseball shape now," Trembley said. "He says he's fine. Let's cross our fingers and hope he keeps it going."

Roberts made his debut Friday, and with Sunday's rainout throwing off original plans, he lobbied Trembley to play Tuesday afternoon following Monday's night game.

Roberts had just one hit -- a double Monday against the Yankees -- in his first three games, but his at-bats are improving as he gets up to speed this spring. Roberts smoked a leadoff double down the right-field line off Boston's Jon Lester in his first plate appearance on Wednesday, and the hope is he will be ready by Opening Day on Tuesday.

Roberts, the Orioles' dynamic leadoff hitter, has been slowed this spring by a herniated disc in his lower back. Since being cleared to play in games, Roberts has done daily extra work on the back fields at Ed Smith Stadium, and Trembley raved about how great he looked running. Roberts made a diving stop at second base to end the first inning Wednesday and he dove back to the bag after Wednesday's double with no problem.

Trembley said Roberts will get Thursday's game vs. the Rays in Port Charlotte, Fla., off, along with most of Baltimore's regular position players.