Why would he accept that deal? If goes back to old form he could get a decent contra for next year. Unless the team option is for 12 million with a significant bug out that is not going to happen. More likely he signs a minor league contract with an option out.
I think there's a lot of speculating there. I have little doubt he'd be a good mentor, but the rest is a big question mark. Two of the last three years he's had an OPS under .600. Rest doesn't cure age and a career's worth of stints on the DL.