I already posted this on the trade board but figured I would see what my fellow Piston fans thought. I know many will hate the idea of giving up Moose but I think this makes us better balanced and gets us to roster limit of 15 as well.
DET - SAS
Monroe/Jerebko/Singler/Middleton
for
Leonard/Green/Bonner
Pistons
Upside: Better balance and floor spacing plus one less year of Jerebko v Green. The defense would look even better IMO as the fit seems conducive to strengths and weaknesses.
Downside: We lose depth at the C position and would have to rely on Kravstov as the only back up.

Spurs
Upside: They get a big man that should fit great next to Duncan and eventually be his replacement when he retires. They get depth back at SG/SF plus a couple of young players on great contracts.
Downside: They get weaker at SF and get one more year of salary from Jerebko v Green.
END RESULT
Knight/Billups/Bynum/Siva
Green/KCP/Billups
Kawhi/DaTome/Mitchell
Smith/CV/Mitchell
Drummond/Kravstov
We would need to address our back up C issue down the road obviously but if worse comes to worse could go Small Ball and roll with Mitchell as the 2nd or 3rd C if need be.