O'Day hasn't pitched since Sept. 7 because of soreness and tingling in the index and middle fingers on his right hand. He didn't accompany the team to Boston.
O'Day threw only fastballs today, but will mix in his break ball on Tuesday - a pitch that has brought the most discomfort.
The Orioles are aiming to get O'Day ready for the Tampa Bay series that starts Friday night at Tropicana Field. There's an outside chance that he could join them at Fenway Park, but it's not likely to happen. Much depends on how he's feeling after Tuesday's mound session.
Also, the Orioles have removed outfielder Henry Urrutia from the restricted list and placed him on the 40-man roster. A corresponding move will be announced later today.
Urrutia couldn't travel to Toronto because of visa issues related to his defection from Cuba, and he will remain in Sarasota instead of joining the Orioles. It appears that he will stay down there and get ready for the Arizona Fall League that begins play next month.
The Orioles want Urrutia to get comfortable playing the outfield. He's played only three innings in left field over two major league games, mostly serving as a designated hitter and pinch-hitter. Also, the Orioles feel that they have enough left-handed hitters on their expanded roster.
Urrutia, recently chosen as the Orioles' minor league Player of the Year, is batting .276/.276/.310 with a triple, two RBIs, no walks and 11 strikeouts in 24 games and 58 at-bats.
And finally, Steve Pearce has been swinging a bat in Sarasota after receiving another cortisone injection in his sore left wrist. Currently on the 15-day disabled list, he's a candidate to join the Orioles in Boston or later this week.
Pearce is batting .241/.328/.361 with four doubles, three homers and nine RBIs in 38 games.
Update: The Orioles designated Wilson Betemit for assignment to make room for Urrutia on the 40-man roster.
Betemit was 0-for-10 after coming off the 60-day disabled list. He missed most of the season after tearing the PCL in his right knee in late March.
Betemit is a free agent after this season. His contract with the Orioles included a $3.2 million vesting option for 2014 if he achieved a combined 700 plate appearances over 2012 and 2013.
The Orioles will keep left-handed hitting first baseman Dan Johnson on their expanded roster.
"Wilson is a popular player on our team and a hard-working ballplayer, but he just couldn't overcome his injury to make a contribution to our team this year," said executive vice president Dan Duquette. "In fairness to him, I don't know that he's 100 percent. We were running out of time. I think he needs more at-bats and he didn't really have that opportunity."