Just a reminder to the enthusiastic and imaginative that Dee comes in initially to fill the bottom spot on the WR depth chart. Every true freshman is months ahead of him in knowledge and preparation.
He will have to learn the plays, the routes, the blocking assignments, the reads, the offensive calls, the signals from the sidelines--everything--and it may all be totally new to him.
Yes, I guess it's possible they could put Dee out on the field to receive a WR screen and see what he could do with that. But what if the defense switches, making that play, that route, the wrong call? What then? Will he know his assignment in the play Milton switches to? Do you waste a time-out to get him out of there? And even if he successfully runs one play, there will still have to be a substitution for him, which allows the defense to also substitute. Maybe it's worth it. Maybe not.
These are all considerations that have to be made before putting Dee (and his incredible talent) on the field at WR. He has a lot to learn, and I feel sure the hope is that he could be ready to play if absolutely necessary in 3-4 weeks. But we need to understand that he has been moved there initially as insurance against losing 3 more WRs to injury before this season ends.
As another way to inform and manage our expectations, consider that Iamaleava joined the team in time to participate in Orange Bowl practices. Would you have expected him to play QB in the Orange Bowl?