My take on Jeff Green ...
Jeff Green is a poor man's Tayshaun Prince.
He has been played out of position for the past three years which is the only reason his defensive statistics are as bad as they are.
And those numbers are spot on, Jeff Green is often a defensive liability at the four. He doesn't have the size or heft needed to matchup at that position. He can give quality defense against some quick/undersized PFs, perimeter based fours and combo forwards like himself as a power forward. However, he cannot matchup against PFs with good size, bulk and/or tall PFs.
As a small forward, Jeff Green is a good to very good defensive player with excellent defensive potential. He is also a solid rebounder vs the liability he is at the four spot.
He has solid ball-handling ability, good passer, has a post game, decent jump shot. He has a well rounded skill-set offensively that badly needs refinement for him to become a high quality scoring threat.
In terms of creating mismatches against opponents ... as a PF, his main asset is his quickness advantage. As a SF, his best asset is his size and strength. So he should play quite well against teams with undersized SFs or two guards masquerading as SFs. Against big SFs, say Marvin Williams, Jeff Green will have a tough time creating his own shot and will need to rely on others to create openings for him.
Jeff Green is a much more consistent shot-creator at the four than the three (quickness advantage at PF happens more regularly than his size advantage at SF).