Check out what Markieff has been doing lately since Jeff Hornacek was fired:
20.6 points, 7.6 rebounds, 4.6 assists, 2 blocks, 1.0 steals, 5.8 FTA, 44.8% / 33.3% / 72.4%, 34.8 minutes per game, 5 games.
Now, do you want a guy on this Celts team that only started playing well this season when his coach got fired and the trade deadline drew near?
Maybe not.
On the other hand, a lot of words have been written lately about the rehabilitation of Evan Turner's career thanks to Brad Stevens.
Why can't Brad do the same thing for Markieff? He seems to be a mentally and emotionally fragile player who will need the right influences around him and a significant role to keep him engaged.
All of that is less than ideal.
Still, Markieff has the kind of offensive talent and versatility that could help take the Celts up a notch, even while he is not the caliber of player that is really going to entirely change the game for the team.
If a deal for a major name isn't available around the deadline, the Celts could do much worse than trading for Markieff. I'd revisit the idea of trading Sullinger, who will likely get paid a lot more than $8,000,000 per year this summer, along with a couple of second rounders or perhaps the Mavs' 2016 1st, and filler (e.g. Jerebko).
Counter-argument --
NO! We don't want to mess with team chemistry for a marginal upgrade.
Plus, Sullinger's numbers leading up to the All-Star break look pretty good too. Maybe he can put together a decent second half and add some offensive competency to his significant contributions defensively and on the boards over the first half of the season.
Making a move just to make a move isn't something the Celts need to do.