Thompson will take a back-seat again next year once Andy Varejao returns to the lineup. And those front-court minutes will be crowded w/Speights, Zeller, and Jones all fighting for Front Court Minutes. And, they'll sign another big man after this off-season when they'll rid themselves of Luke Walton's ridiculous contract.
Sanders is a machine (throwing up dub-dubs), has the starting position (he OPTED to come off the bench to start the season) and leads the league in a very difficult category: Blocks.
And, if you decided to trade either of them, what's TT gonna get you? A Tier-3 role player? Sanders can fetch you some serious players as he's ranked so highly.
Nothing wrong w/Thompson down your roster as a role player; but Sanders is the real deal.