There is no way we keep Al Horford next season at $26.5 mm. I misunderstood how the guaranteed portion worked. It thought that as long as we didn't make the finals, we could keep him at pay him at the guaranteed $14.5 mm portion, which would be palatable if he continued to start. But if our only choices are as outlined by Roy, there is no way we would be able to keep him. We would either trade him or work on a buyout or stretch him.
Now the Theis trade makes more sense; he would basically replace Al next year in a similar role.
I'm really not looking forward to a buyout or stretching him. So if we don't keep him we'd have to trade him. A team that is coming of a fairly successful season is not going to look at Horford as a viable trading option. So we need a trading partner that's already in rebuild mode or has been so disappointing that they want to break it up.
With a contract as Horford you have to be little imaginative. And things are unpredictable (who would guessed that Porzingis would go to Washington or Sabonis to Sacramento?). The options I'll be naming sometimes seem farfetched on the other hand the Celtics wouldn't be very interested if they can't get back a player at the same level or with a lot of upside.
In the proposed targets I won't be offering picks or assets or whatever, they're a given dependent on the target level. In the same way some salary filler from either side may be needed, but that's also a minor detail in the grand scheme of things. The teams I'm disregarding are Heat, Cavs, Bulls, 76ers, Raptors, Suns, Warriors, Grizzlies, Jazz, Nuggets and Clippers (because of Leonard returning). Potential targets:
Nets: Durant (or Harris)
Hornets: Hayward (or Rozier)
Hawks: Collins (or Huerter + Hunter/Okongwu)
Wizards: Avdija (S+T Beal seems impossible)
Knicks: Randle
Pacers: Brogdon
Magic: Isaac
Pistons: Grant
Mavericks: Hardaway Jr
Timberwolves: Towns (or Russell)
Lakers: Davis
Pelicans: Williamson (or Ingram or Valanciunas)
Trailblazers: Lillard
Spurs: Poeltl
Kings: Barnes (or Fox)
Thunder: Gilgeous-Alexander
Rockets: Wood
A couple of these options look really crazy like Durant, Hayward, Towns, Davis and Williamson. The most interesting and realistic options to explore are
Collins (Hawks), Brogdon (Pacers), Grant (Pistons), Lillard (Trailblazers), Barnes (Kings) and Wood (Rockets) I'd think. The teams in question have various reasons to actually trade these players and in certain negotiations (for instance the Hawks) a 3rd team could be included.
Grant (offensive rank issue), Lillard (salary issue) and Wood (attitude issue) would be on my back-up list. I'd phone the Hawks and Pacers first with the Kings as my 3rd option. Collins would be kind of an ideal fit and Brogdon should be attainable as long as the Pacers don't have any resentment from the failed Hayward negotiations.