I hate to throw cold water on this thread, but I think there is a better than 50:50 chance Ainge moves his draft pick this year in a trade, especially if he keep all of Langford, Nesmith and Pritchard.
If the Celtics are going to be in the tax, Stevens is going to need to give it his all and make a run for the title and adding yet another mid first rounder that needs development to the team makes that a lot more difficult to do.
But, let's say Fournier doesn't re-sign, if Ainge does make the pick, my binkie in that range is Franz Wagner. Good size swing. Can hit the three. Great free throw shooter. Very good rebounder that should get better when he adds some size in the weight room. Doesn't turn the ball over. Excellent at the fundamentals like proper positioning, boxing out, making the right passes, finishing at the basket at a high rate, etc. Not a great creater of his own offense but an efficient scorer.
But, he will need to work on the 15-23 foot shot and his defense. His handle could use some work to if he ends up sliding into the 3 spot a lot. Should be interesting to see what his combine numbers will be.