St. John's is buying out Mullin (probs $4M - source), will have to pay Hurley's buyout which is $2.5-$3M (source), and will end up having to pay Hurley another $2.1M or more per year (which is what he's making at ASU).
I doubt they have a replacement ready. I don't think the administration wanted to do this, based on the signals they had been sending up until today. Somebody convinced them, correctly, that Mullin couldn't coach. What he did this year with that talent was a travesty worse than anything Ollie did.
They returned almost their whole rotation, added Heron, and fell 15 spots in KenPom. The Heron effect notwithstanding, that's so atrocious.
I don't see Bobby leaving P5 for non-P5, especially one with a similar budget, unless he's just not happy there for some reason.
Sidebar story: What a flipping wasteland the Pac-12 is becoming for hoops. 'Zona is looking at a long dry spell once the FBI kicks in. AZ State loses Hurley. UCLA is a mess. Washington is probably in the best shape, but they're kinda where they're always at. Oregon and Utah are fine I guess.
Or Tempe, but most serious coaches aren't chasing after coeds. Even if Bobby Hurley's a dislikeable Pukie, he's never appeared to be a coach prioritizing coeds over seriously coaching. Now, some potential ASU recruits might allocate a bit of time to the former.