He's praised Puljujarvi pretty extensively recently and I think it's clear the only reason he was scratched the other day was they wanted to give McGroarty one more look.
As long as Puljujarvi keeps this up, he'll be in the lineup.
Honestly, I think they'll go to DOC up there again first before putting Rakell at LW. Plus, Bunting-Geno-Rakell is killing it right now. 68% Corsi For while together, 3-1 GF to GA, 17-5 scoring chances for vs against, and 8-3 high danger chances for/against.
Sullivan's stubborn, but I don't think he's going to take apart a line that's working that well.