I think Harrison Barnes to BOS's TPE is a much more likely deal in the offseason than it is the deadline. On both ends:
BOS - For this year, we are literally hard capped at the tax apron. We are most likely PRACTICALLY hard capped at the luxury tax line. It just doesn't make sense for us to go over the tax line this year. Acquiring Barnes for the TPE and staying below the tax is a challenge. This offseason, we won't be hard capped and it's not practical to stay below the tax so Barnes makes much more sense for the TPE.
SAC - I don't think Barnes is going to return an overly impressive package of assets. I think the best part of any return for him would be the salary flexibility. They are in a position where if they want to re-sign Richaun Holmes, they are going to have to renounce all of their exceptions to use cap space because they don't have full bird rights.
https://www.spotrac.com/nba/sacramento-kings/cap/2021/Spotrac has them at $105.6M for next year. That includes CoJo at his full $12.6M salary vs, $2.4M buyout but let's say the delta there that they'd save ($10.2M) is what they'd have to spend on Holmes. To do that, they need to renounce all other FAs and the MLE. Their draft pick likely takes them most of the way up to the $112.4M cap.
Moving Barnes doesn't eliminate the need to do so, but gives them the wiggle room to still sign other players. You could basically sign Holmes and then use the cap space on 2 MLE type players to try and build a bit of a younger core around Fox/Haliburton/Hield/Ramsey/Holmes/2021 draft pick/Woodard. Just might make more sense to turn the money allocated to Barnes into two younger players and recoup the small asset I think you could get for trading Barnes into a TPE or cap space.
But end of the day, if Sac doesn't want to keep Holmes or they don't see any FAs they like to spend on otherwise, then there's no need to move Barnes. Hence the offseason making more sense where they can see if scenarios that require the spending room make sense.
