So now he is "not good" as opposed to "about average"? Let's just say that myself and many others disagree with your opinion.
Jeremy's defence has definitely improved over last season and is improving over the course of this season. His ability to fight through the screens as of late as been great as I've noticed that he's been able to body up against the ball-handler just as the screen is coming and avoid it a lot more often then before where he'd get blown up. Maybe it's better communication by the big man, but he's doing a better job of defending the pick and roll plays. He also does a great job with his pursuit. He's not really quick laterally, but when he gets beat, he does a great job recovering and I think it's because he uses his great explosive first step to close the gap. There have a been a lot of plays where the opposing guard beats Jeremy, but then are caught off guard when he recovers either by stripping the ball, blocking the shot or contesting the lay-up.
Context is necessary, since Novak usually face weaker opponents as assignment and he's played in limited minutes with energy. He also has DOY in Chandler behind. However, Novak was doing great defensively since last season. If you search NBA dish section, there're threads specifically talking about how Novak became weirdly good defensively last season. Those are comments from fans watching the game. JVG also was impressed by his defense last season, and commented on braodcasting about how Novak playing 3 instead of 4 got him size advatage and totally changed the defensive picture.
torocan and durvasa are the OG's of logistics and objectiveness of this board. That said, I agree with torocan here. Synergy and advanced metrics can be misleading slightly with some caveats that should be combined with the "eye test" (which by itself is the most erroneous method of judgement). And you should throw out the first few months for Jeremy because he was coming off the injury and is just clearing getting back into form, and Morey even confirmed he is not 100% yet. But you just need to look at some of the gifs and video (ie that video against Jennings) to see that he CAN be a good defender at times, atleast in terms of staying in front and getting steals. What he isn't so great at is contesting after the fact. He tends to foul the guys or doesnt have the great instinct yet to use his size to contest the shots once he forces his guy into a jumpshot. Thats what he did (or rather, couldn't do) against Lillard a while back for that game tying shot.
