Green versus say NY and Miami's benches should work. Off the top of my head, he should have good matchups there. Help me out Who.
Jeff Green will be particularly useful as a power forward against New York. He'll have a matchup advantage against Jared Jeffries and/or Shawne Williams. He'll also be able to take advantage of NY's only backup wing, Bill Walker.
Keep KG at the five on Amare and put Green out there as a four against Jeffries or Williams and Boston can really nullify NY's usual advantages by going small.
New York have one, possibly two players, who can defend Jeff Green well. Carmelo Anthony certainly can and Landry Fields is maybe ... although Fields is a bit small to defend Green in the post but he should do just fine otherwise.
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Miami only have one player who can defend Jeff Green and that's LeBron James.
Their backup wings, Mike Miller and James Jones, are too small physically and too vulnerable defensively to matchup against a power three like Jeff Green.
LeBron will likely be playing anywhere from 40-44 minutes a night in that series though so Jeff Green's court time with a matchup advantage could be quite short.
Paul Pierce will be LeBron's principal defensive assignment though so they might be able to free up some more advantageous opportunities for Green by playing him alongside Paul and going big on the wings. That may depend on Green's ability to defend Dwyane Wade which is a question mark to say the least. So it's unclear whether that will work and/or how many minutes they can get out of it if he can't defend Wade. Hard to know.
Jeff Green will be terrific against Miller and/or J.Jones.