If the Asik for a projected Lottery-Mid 1st rounder and Mozgov for 2 projected Late 1st rounders are the going rate, the price is going to be high for Dieng.
That said, Dieng has the post game, mid-range shot, athleticism, and defensive ability to average double doubles while providing good rim protection as soon as next year. Based on last year's production (9.8 PPG, 8.3 RPG, 1.7 BPG in 30 MPG) and a reasonable projection of his progression, his ceiling might be around 12-12 w/ 2-3 blocks per game, which is borderline All Star/DPOY production. You don't pass up on that for the idea of (insert college player drafted at #16 or #28); for all we know, Upshaw can be Fab Melo.
Dieng's 25, but he's going into his 3rd season in the league, which I think one can safely assume that this is not the finished product.
If you can get Dieng for Olynyk, #16, and #28 (choose 2), you make it.