Doc Rivers believes coaching LeBron James is the toughest job in the NBA.

David Blatt had that job for the past year and a half but was relieved of his duties by the Cavaliers on Friday and replaced by Rivers’ protege, Tyronn Lue. Rivers, the Clippers’ coach, was happy for Lue but felt badly for Blatt.

“Blatt’s a heck of a coach and is doing a heck of a job,” Rivers said before the Clippers faced the Knicks on Friday night at Madison Square Garden. “He had the most scrutinized job that you could possibly have. I think the reward for coaching LeBron is you get scrutinized. It really is. It’s hard.

“You have a great record, the best in the East, and you get fired for it. Unfortunately, being in this as long as I’ve been in it, you see it all the time. It’s happened to me. It’s tough.”

The Cavaliers reached the NBA Finals last season and were an East-best 30-11 despite being without Kyrie Irving and Iman Shumpert for extended periods to start the season.

Mavericks coach Rick Carlisle, the president of the NBA Coaches Association, had some strong words on the Blatt firing.

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“I’m embarrassed for our league that something like this could happen,” Carlisle said. “The other side of this is a good man has been liberated.”

Blatt’s last game ended up being a victory over the Clippers. Rivers gave Blatt credit for some of the decisions he made in the game.

Lue was the Cavaliers’ associate head coach and worked for Rivers with the Celtics and Clippers. Rivers hadn’t spoken to Lue yet, but he said when he does, he will have some advice.

“I don’t know if anyone’s ready for that,” Rivers said. “That’s a tough one, middle of the year. Taking a job in the middle of the year is very hard.

“It’s just hard, that’s what I will tell him. It’s just a hard spot to be in. That’s all I’m going to tell him. He’s got to be him. They’re probably going to do most of the same stuff. The defense and the stuff they’re running was with Ty and Dave, anyway. It will be interesting to see the changes.”

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Derek Fisher, a teammate of Lue’s with the Lakers, didn’t want to discuss what he thought of him before Friday night’s game.

From the outside, it appears James had a hand in this move. Fisher was asked how important it is for a coach to have a good relationship with a star player.

“I’m too early in my career to know exactly what the formula is, other than just trying to win as many games as you can,” the second-year coach said. “But there have been some really good coaches that have been relieved of their duties in the last few years that have won a lot of games. So if you get caught up in those dynamics, you’ll still end up losing.

“You just have to focus on what you can do, and whatever decisions are made, they’re made. But you can’t worry about it too much. Because it will distract you from doing the job you need to do.”

Fisher didn’t have “an overt or strong reaction” to Blatt’s dismissal.

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“The news of anybody losing their job, regardless of the profession, is not good news,” he said. “You have to do the best you can do, focus on the things you can control, which it seems like he did. But when you work for someone else, those decisions lie in other people’s hands and you have to live with it.”