No. 1: Darius Garland
The Cavaliers continue to maintain that they plan to keep the "core four" together through the offseason and see how they can play under a new head coach and offensive system. That may just be a public stance to ensure their trade value stays high, but it's likely their intention to try and keep the group together.
If they were to move one player, Jarrett Allen makes a lot of sense given the offensive suicide it is to play two non-shooters at the same time, but Donovan Mitchell's camp has made it clear that he loves playing with Allen. Moving on from Evan Mobley is untenable because he still boasts the upside to be a Defensive Player of the Year and a 20-point-per-game scorer (or more) on offense. They can't give up on that yet.
That leaves Darius Garland, and his agency Klutch Sports has already floated that they may ask for a trade if Donovan Mitchell re-signs. That seems like more than a means of negotiating for more touches; Rich Paul and Klutch Sports are not afraid to exert real influence to get their players to new teams.
That seems like the most likely outcome here. Donovan Mitchell hasn't signed anything yet, and if he refuses to sign an extension then the Cavaliers have to trade him -- he will have no shortage of suitors. Once he signs, however, this is clearly his team, and the ability for Garland to shine as the primary offensive engine will be extinguished.
That's why Paul and Garland will go to the Cavs' front office and request a trade. Despite a down season he will surely have a lot of interested teams, from the Orlando Magic to the San Antonio Spurs to the Los Angeles Lakers. The timing will be key; is this a conversation that happen by July 1, or does it happen later in the summer like Damian Lillard's slow trade process last summer?
The Cavaliers love Garland, and he is a great player. The team may convince him to stand pat until the trade deadline to see how he and Mitchell mesh under Kenny Atkinson's system and to allow his trade value to rebound. At some point, however, the writing appears to be on the wall: Darius Garland is not long for the Cleveland Cavaliers.