One of the most industrious forwards in Super League, Massey joined the West Yorkshire club at the age of 15 and recently marked his 250th appearance.
Now aged 31, it looks like he could see out his career with Castleford.
Powell, of course, will not be the player’s coach next season as he moves to Warrington Wolves.
But he said: “Generally, I can’t think of too many times throughout the last eight years when I haven’t picked Nathan Massey if I am looking for our best team.
“I think that probably sums it up.
“First and foremost, as a bloke he is top-class.
“He is Castleford through and through.
“He has been one of the players I have been able to rely on so much during my time at Castleford and I am pleased for him, to get his future settled and for Castleford as well.
“He is part of the fixtures here and I think he has been at his best this year.
“He has obviously wanted to earn a new contract and he has been one of our best front-rowers.”
Massey played in the 2014 Challenge Cup final and - having helped Castleford roar to the League Leaders’ Shield - the 2017 Grand Final.
He is often described as an ‘unsung hero’ and Powell said: “The things that are regarded pretty highly in an environment are the little hard work things that you don’t always see - the kick pressure in particular.
“He has probably been our best since I’ve been at the club.
“Because the boys have been defending - and usually the middle-unit players have to make a lot of tackles - to then at the end of that put pressure on the guy who’s kicking the ball, which then supports the man catching the ball, they’re the little things that are valued so highly.
“He does big minutes and you don’t always see that in middle-unit players because they get put under a lot of stress.
“His third-man tackling, from a defensive perspective, is consistent, he is honest as the day is long.
“That is so critical to success and Nathan is one of the most honest guys I know.”
Massey is delighted to be staying at Wheldon Road.
“I am obviously over the moon because I’ve made it no secret that I wanted to stay here,” he said.
“This next two years is going to be big for me and it will take me to near the end of my career.
“I’ve said that if it was possible to finish my career here and this contract might take me to that.
“I am proud to play for this club and I feel privileged to pull the shirt on every week and hopefully the next two years are going to be another good few years for the club.
“There is plenty of motivation to finish this season on a high with Powelly [Daryl Powell] leaving after what he has done for the club. It’s a bit of an end of an era for us this year so there is plenty of motivation in there to win some silverware.”
Ex-Hull FC coach Lee Radford takes over in 2022 and he said: “He (Massey) epitomizes what Castleford is all about really.
“He is honest, hardworking and does things that the untrained eye doesn’t see.
“He’s really tidy in and around the ruck and it’s because of players like him that Castleford have been as successful as they have been in seasons gone by. I’m really looking forward to working with him.”
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