I think all of the receivers are expected to be on the same page at this point of the season, but that doesn’t change the fact that we’ve seen plenty of examples of WRs who haven’t panned out.
Normally, one would expect more than 7 receptions in week 14, particularly when Edelman, Mitchell, and Hogan have all missed significant time, and the player in question is a former first round selection. I think it’s fairly obvious (and was discussed on the TV broadcast, whether you choose to accept that as fact or not) that Dorsett is still not fully on the same page and that he’s continuing to try and learn the system.