The article mentioned Wallace as as being a pleasant surprise. It didn't say he had a farts chance in a wind storm of moving up past 4th on the depth chart, not that you were implying that at all. Just that he seems more physically ready to play than what might be expected.
Seems to me that it would take dramatic injuries for Wallace to play more than a few carries here and there in garbage time, as you implied. Short of two of Singleton, Allen and Potts getting multi game injuries Wallace's path to burning his redshirt seems to be his being a KO returner too good not to use. i.e. on a par with what Singleton brings as a KO returner, but with the staff wanting to not risk injury for Singleton.
The staff brought Potts in to play a role and with Potts being a physically mature RB that has proven himself in the B10 against the top teams in the B10 it seems pretty likely that the staff will carve out a reasonable role for him which seems to be stop sign for any freshman RB burning their redshirt as a RB.