My prediction: Horford opts-out and then re-signs with Boston on a 4/75M deal.
Not sure if'd want to make that kind of commitment.
Horford's missed alot of games this season and worry if we kept him for another 4 years that he'd continue to gradually decline, physically.
For me, best case scenario is he opts-in for one more year and that's it.
I like Al, but also feel age and mileage and is starting to catch up to him.