Yes teams will tank games via minutes allocation, DNPs, and just not trying very hard late to setup matchups they like, to help their draft picks, or manipulate the bracket to help themselves.
What players usually don't do is lay down against teams in the playoff race for no reason, they'll usually try and give it an honest go because players don't want to throw a game that effects other teams playoff races if there isn't a reason for it.
You could see this in the Toronto/Miami game and even the Boston/Orlando game. Neither result really matters to BOS/TOR much but the players on the court still tried hard.