Mac has never wavered in his support for Geno which should mean something considering how quick he can be to call out poor play and players. When asked about Geno's play, he again stated that he played very well this year and that although he did have the int issue and needs to work through that, he was also quick to reaffirm that many of those errors were 'team' errors. Take that how you will but its pretty evident Mac understands WHY much of the poor play on offense occured and isnt so quick to do away with a qb he considers to be the answer for the Seahawks at this point in time.
I expect them to try to keep Geno here next year and if they can work out a deal that protects them from paying top dollar for a 38 year old player on the decline and leverage the moment they have to maximize his potential in a system that supports him, they will do it. If they thought Geno was the same kind of liability that Grubb was and that riding with him would result in them underachieving for a 4th consecutive year, their plan would be to aggressively pursue other options.
This seems to make it clear that in the HCs eyes, Geno can take them where they need to go right now and best case is getting the guy to replace him on the bench and learning from him asap.