It looks like Wright's salary would put us very close to the tax, but not over it. Still, Sham is out of date and HoopsHype's salary pages aren't always 100% accurate, so it's possible that Wright would nudge us over the tax line. Wright for Hollins would seem like a no-brainer from our side, but the Celtics are probably trying to get some value out of him.
But that's kind of what I see the exception as useful for - taking a salary flyer on a guy. They only last for a year, and it's not like we're terribly likely to find a better deal for nothing. I don't remember the last exception deal that turned into a steal. I suppose there must have been one, but nothing sticks out in memory. Since the trade exception is use-it-or-lose-it, I would say in this case to use it unless there's an obviously better deal soon to be available. Of course, that depends on the Celtics actually dumping Wright for nothing and our team being able to handle the salary cap implications of absorbing him.