The Wings have 12 forwards and 6 defensemen set on the roster. The candidates for the remaning 3 slots are, in age order:
Downey, Hartigan, and Sopel will have to show considerably more than Ellis, Grigorenko, and Meech due to the age difference, and the fact that the second group of three has their best years ahead of them, while the older group is on the back side of the hill. We know they will have at least one forward and one defenseman. We'll assume that they will go with the guys on the list who are both the highest potential and the youngest; Grigorenko and Meech. Meaning we now have the spare forward and spare defenseman, and the remaning slot can be used for the best available player from the list. Hartigan and Downey are career journeymen, and Ellis has yet to crack an NHL roster. Sopel OTOH is a guy many on here felt could replace Markov in the top 4...so I think that choice is obviously a good possibility. However, Red Wings Central has a 23-man roster posted under the organization chart that includes Grigorenko, Ellis, and Meech, but this may be a result of eliminating guys who are on tryouts. Ellis is also removed from the prospects list on RWC, another sign which would seem to indicate they expect him to be on the final roster.
He needs to get used the NA style of hockey, that means he needs to play. Grand Rapids will allow him a chance to develop with all the playing time he can get. Keeping him as a 13th forward does nothing to develop his skills. Having a 13th forward with some grit that can play 5-7 minutes a game and bring some energy is needed. Grigorenko is not a bottom 6 player, he's not a grinder. If Babcock keeps him on the roster at the expense of the others you mentioned, he defeats his own message which is to work hard, know your role and play physical. Grigorenko, so far, is none of that