the reason this could be bad is obvious... stevens already had chemistry & rapport with hasselback (albeit timing may have been disrupted with stevens being out so long)...
less obvious reason it could be good... sometimes with an inexperienced QB the TE is attractive target as they are generally quick hitting throws between the hashes where they are shorter, higher percentage and without degree of difficulty... so maybe OC more likely to target the TE to build QBs confidence, & more likely for QB to look for if things break down as they will be in close proximity...
wallace in limited action doesn't look totally inept... i wouldn't start him if i had somebody better, but if you don't, i think he could get 3-4 receptions... TD almost certainly less likely than it would be with hasselback, as new guy less likely to sustain drives & get in red zone... & it doesn't help that SA still out...