Thomas entered the Vikings' medical tent before heading to the locker room during Saturday's preseason contest versus the Cardinals, Andrew Krammer of the Minneapolis Star Tribune reports.
Thomas took a big hit on a muffed punt return in the second quarter, though it's unclear exactly what injury he could be dealing with. The undrafted rookie out of NC State did not record a catch before exiting Saturday's contest, and he is likely competing for a spot on Minnesota's practice squad as a deep reserve option at wideout and/or punt returner.