Betemit hasn't started the last two games against Boston right-handers Josh Beckett and Aaron Cook. He was expected to platoon at first base with Mark Reynolds after Manny Machado became the regular third baseman.
Betemit is hitting .306 with 11 home runs against right-handers, compared to .143 with one home run vs. left-handers.
The MRI should determine whether the soreness is caused by tendinitis.
Betemit's wrist apparently feels a little better today, but not enough for him to play. He tried to hit this afternoon before manager Buck Showalter made out his lineup, and Betemit is considered day-to-day.
The wrist apparently began to bother Betemit on Monday, the same day that reliever Troy Patton showed up at Camden Yards with a sprained right ankle. Showalter joked that he's going to eliminate off days or hide in his office.
Reynolds homered twice and drove in four runs last night as Betemit's replacement, and his defense at first base has been an asset.
Patton and Jim Thome, on the disabled list with a herniated disc in his neck, are expected to leave the team later today. Patton is headed to Sarasota, and Thome will fly home to Illinois.
Jason Hammel is still scheduled to throw another bullpen session on Thursday. His right knee is feeling good.
For the Red Sox:
Jacoby Ellsbury CF
Carl Crawford LF
Dustin Pedroia 2B
Adrian Gonzalez 1B
Cody Ross DH
Jarrod Saltalamacchia C
Mike Aviles SS
Scott Podsednik RF
Nick Punto 3B
Aaron Cook RHP
According to the Red Sox, Ellsbury's 37-game hitting streak against the Orioles is the second-longest since 1900 for any player vs. any team. Vladimir Guerrero had a 44-game streak vs. the Rangers in 2004-06.