Cruz was scratched from Thursday's lineup against the Marlins due to back tightness, Mark Zuckerman of MASNSports.com reports.
Cruz was originally scratched for undisclosed reasons. The severity of the issue is not yet known, though manager Dave Martinez said Cruz is scheduled to undergo an MRI on Friday. Yadiel Hernandez took over as the designated hitter, and Lane Thomas would also likely benefit if Cruz is out for an extended amount of time.