"Don't know the extent of it. Certainly, he's day to day at this point," said Farrell, who added that Middlebrooks will undergo tests Wednesday. "He strained it on that infield base hit and when he was leading off coming back to second base in that next at-bat, it looked like it grabbed him again. Got him out of there [for] precautionary [reasons]."
Middlebrooks has dealt with a number of injuries in 2014 and past seasons. He's played in just 35 games this season because of a calf strain he suffered in April and a broken right index finger in May that sidelined him for more than two months.
After hitting 15 home runs with a .835 OPS over 75 games in 2012, the 25-year-old Middlebrooks has been hampered by inconsistency at the plate and a slew of injuries the last two seasons.
Steven Petrella is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.