The Summer? No chance.
He only signed a 4 year deal in April his words were "couldn't be happier". His a Celtic fan and his not leaving after 1 year. He keeps making the point this is just the start and there is a way to go.
Yes he could possibly win everything domestically in season 1 but that doesn't mean that all what he wanted to achieve.
He's made a massive statement and proved his point which is why I think there's more than a chance he goes this summer - but if he doesn't, then he probably stays ultra-long-term. His stock probably won't ever be any higher than it is now and the whole of Europe has seen his vindication after walked out of Anfield with his tail between his legs.
If you're him and you get a mega-offer from a PL team, I'm not sure it's possible to refuse. The chances of repeating this season's feats in 2017/18 are almost infinitesimally small and so next season probably doesn't ever taste as sweet, especially if they end up having a miserable CL campaign.
I just wonder that, when an offer comes in this summer - which it will - Brendan looks at it and thinks along similar lines - and my point is, that if he doesn't then he probably does stay there for a decade or more and keeps scooping up the titles and becomes a God. I personally don't see a half way house.