MAVS NEWS:

[mvossman]

Don't listen to all of these fool talking heads. Klay has fallen off that much. People keep saying that he fell off a cliff. That's because he chose Dallas over LA. He's still an 80 out of 100 on defense. It's just that he was a 95 out of 100 in his prime. He can still defend very well. I only consider DJJ about an 85 on defense by comparison. 

Last year Klay was running guys like that into help defense. He never could stay in front of guys that were that fast. But, he can still slide them into help as well as block from the back side with his length.

I think you are underselling what we got from DJJ and overselling both what Klay was defensively, and what he is now.  There is a fine line between running a guy into help defense and blow by.  There will definitely be a drop off in defense, especially when the primary ball handler is a quicker guard.  The hope is that moving Lively into the starting lineup will help mitigate some of the defensive hit, and the improvement in offense will more than make up for the loss in defense.