It's being reported by Ian Rappoport per "sources", so I would guess it's pretty legit. O'Brien famously gives "minimum two year commitments" to teams he signs with, and that two year period with Alabama ends in a week at the Sugar Bowl, so I'm guessing the Pats and O'Brien may have had some initial conversations.
Feels like they're gearing up to announce his signing for 2023 shortly after the Sugar Bowl to try to start controlling the offseason narrative as far as the Patriots offense being a dumpster fire. Instead of free agents in March saying "I don't want to play there, that offense looks like trash", there'll have been a few months of narrative about how it'll be improved because they got B.O.B. in there, etc. Potentially, anyway.
I think O'Brien is a guy Mac likes/wants too. Mac can trust O'Brien to know what he's comfortable with because O'Brien just came from the offense that Mac was running two years ago.
I also kind of feel like Kraft might want O'Brien as the BB successor... just a thought. Seasons like this last one probably makes Bill start thinking about hanging them up sooner rather than later. I wouldn't be surprised if he's ready to head out in 3 or 4 years and we've heard that the Krafts had O'Brien in mind as a BB replacement in the past so if they keep him around as the OC for a few years it may end up working out that way. I'd be fine with it personally. Just keep him out of the draft room for gods sake!