Help me spend my money!!!!!!
With your budget and the D7000, I'd go with a used 80-200 F2.8 D (the two ring version). It has no VR, but VR won't really help you anyway when your target is moving (and you mentioned sports). I have one that that I shoot cross country and baseball with on my D7000 and it works great. I bought mine from KEH for somewhere around $800 I think.