Kevin Garnett didn't give the Nets much during the regular season, which is what you would expect for a guy in his 19th season in the NBA. However, even in the post-season, Garnett has been pretty much running on empty. He is averaging only 20 minutes a game and not making much of an impact when he is in there. In Game 1, he had 0 points and 4 rebounds on 0-2 shooting in only 16 minutes.
When he's in the game, he's pretty much just a placeholder. While he still starts, Jason Kidd takes him out after only 4-5 minutes and he usually doesn't put him back in until the very end of the second quarter. It's not like the Nets desperately need KG out there either - Andray Blatche is more of an offensive threat while Mason Plumlee gives them more energy and athleticism on the glass and the defensive end.
At this stage in his career, KG can't really establish deep post position against bigger 5's and he no longer has the quickness to take them off the dribble. He doesn't have much lift in his legs to finish around the basket - he's pretty much only effective as a spot-up shooter from 15-20 feet, which can be taken away by a defensive player who presses up on him and forces him to put it on the floor.
On the defensive side of the ball, KG can no longer move his feet and guard players on the perimeter. The Heat were able to put him in pick-and-rolls with Chris Bosh and dictate the action - either zipping the ball to Bosh when KG shows or letting the guard attack the basket or get an easy shot when he goes under. At this point in his career, he's basically a backup center or a starter in name only.
For a guy with his pedigree and pride, the real question is how much longer he wants to keep playing. He has one year left on his contract but he's made well over $300 million dollars in his career so it's not like he needs the money. Jason Kidd has shown that he has no problem playing the hot hand and going with the best players in his rotation - there's a greater than zero chance KG falls out of it next year.
At this stage in his career, KG is strictly a 5. So when Brook Lopez comes back next season, there won't be all that many minutes for him in Brooklyn. With Lopez, Plumlee and Blatche in the fold, KG's biggest contribution could come as a veteran leader and a mentor in the locker room. That's pretty thin gruel for one of the greatest players of all-time - he could be asking himself whether he even wants to get himself ready for the grind of the next season.
If the Nets are going to have any chance in this series, they are going to need more from KG than what they've gotten from him in the playoffs or the regular season. If he has anything left in the tank, it's now or never for him. With everything else that has been going on around their team this season, there hasn't been too much talk about it, but I wouldn't be surprised if this is the last we see of KG in an NBA uniform.