Justin Masterson gave up four runs and walked six in 4 1/3 innings Wednesday in a loss to the Rays.
Hanley Ramirez (shoulder) is expected to begin taking dry swings on Thursday.
Red Sox pitching prospect Henry Owens bounced back with a strong effort Tuesday for Triple-A Pawtucket, limiting Toledo to one run on five hits over six innings.
CBS Sports' Jon Heyman reports that Hanley Ramirez (shoulder) "is said to be feeling better" and hopes to return to the lineup "in a couple days."
Red Sox manager John Farrell indicated Tuesday that the team might give Hanley Ramirez (shoulder) a week to improve before deciding whether to place him on the disabled list.
Koji Uehara retired the Rays in order to pick up his fifth save, closing out a 2-0 win versus the Rays on Tuesday.
Rick Porcello scattered eight hits over seven scoreless innings to pick up the win versus the Rays on Tuesday.
Mookie Betts provided all of the offense the Red Sox needed on Tuesday, hitting two solo home runs in a shutout win over the Rays.
An MRI came up clean on Hanley Ramirez's shoulder.
Allen Craig is in the starting lineup and playing left field in Tuesday's game against the Rays.
Xander Bogaerts went 1-for-3 with an RBI triple, but the Red Sox lost 5-1 to the Rays on Monday.
Clay Buchholz continued to struggle on the mound on Monday, taking his fourth loss after yielding five runs in 6 1/3 innings against the Rays.
Red Sox manager John Farrell said after Monday's game that Hanley Ramirez's left shoulder injury is not a "clear-cut DL" situation.
Hanley Ramirez has been diagnosed with a left shoulder sprain.
Hanley Ramirez left Monday's game versus the Rays in the first inning with an apparent left arm/shoulder injury.