If Day leaves, does Hartline take over? Or too big a job for first time? Does Day even have NFL aspirations?
I don't think either are going anywhere. But I could forsee Harbaugh jumping to the NFL if he gets any flack internally. Especially if a team he is interested in has an opening.
Nah, Hartline isn't remotely ready. Our OC position is open, so it's possible he gets a look. But even that might be a stretch.
To the OP -- Day runs a risk of being fired if he goes full John Cooper. But even losing to Michigan in 1995 and 1996 didn't really threaten Cooper's job because he had elite teams that beat everybody else. Cooper ultimately got fired because in addition to losing to Michigan, he started losing 4 other games.
If Day goes 11-1 most years with Michigan losses, he'll lose a lot of goodwill. But nobody is firing a guy that goes 11-1. He probably beats UGA in Atlanta if that targeting call isn't overturned.
The wildcard is how OSU adapts to NIL. Right now, northern teams aren't playing the game that southern teams are, and OSU has very publicly refused to match big dollar NIL offers to recruits. If their recruiting falls from elite status, then 11-1 becomes 10-2 or even 9-3, and that won't fly. Doubt it comes to that, though. Even without matching the SEC on NIL, he got a top-6 class.
With Harbaugh, who knows. Several inside sources really do think he's gone if he gets an offer, and the only reason he came back last year is because he bombed the Vikings interview. Who knows -- he's a weird guy that's tough to predict.