I’m a bit surprised Horford is turning down a 31MM option for 2020 but it could indicate a few things:
1) he’s looking for long term security instead more money upfront
2) he may not be sold on what is happening in Boston
3) he still believes he’s a top tier player
The reports I’ve read are that he’s seeking a 4 year deal. Boston offered him 3 years.
If you are the Bucks, do you take that chance and throw your hat in the ring? Quite honestly, he’d be a great fit with this team. They could probably get Lopez for less money but Horford (even at 33) is still a better overall player.