Kevin Martin smiled knowingly Thursday after learning that the Wolves had acquired their former franchise player, Kevin Garnett, from Brooklyn. Martin, in his 12th season, knows what’s going to happen inside the Timberwolves’ locker room when Garnett walks in for the first time in almost eight years.

That’s why Martin knew exactly how important this trade was, no matter how much life is left in Garnett’s 38-year-old legs.

“When it comes to teams, and impacts on teams, and on the whole fan base,” Martin said, “I think that was the biggest trade of the day.”

And it’s not because of what numbers Garnett might or might not put up on the court. It’s the manner in which Garnett will compete. For all the young players currently wearing Wolves jerseys — who were children the last time Garnett wore one — Martin has an idea of what’s about to happen.

“That locker room is going to be turned upside down,” Martin said. “The culture of the team, he’ll definitely put his handprint on it. That’s what we needed in that locker room, somebody who’s been through it all, a Hall of Famer. As intense as he is, it’s definitely going to change.”

Fans of Garnett his first time around here already know the way Garnett plays. He has a glare that even Ricky Rubio admitted can scare an opponent. His intensity is legendary. Now young players such as Andrew Wiggins, Zach LaVine and Gorgui Dieng — to name a few — are about to experience it up close.

One of those youngsters can hardly wait.

“It will be great,” Wiggins said. “He’s one of the all-time greats, the best player to ever come to this franchise. He’ll teach me a lot. Practice will be intense. So I’m looking forward to it.”

Keep in mind that Wiggins was 12 when Garnett was traded to Boston. Garnett was long gone by the time Wiggins came here via trade last summer. But, he said, Garnett’s imprint here can still be felt. Now it’s time for Round 2.

“I watched how he played,” Wiggins said. “How he acts. From what I hear, he’s a great teammate. He was loved [here]. So I’m excited to play with him.”

He’s not alone. Ricky Rubio grew up in Spain, when Garnett was putting Minneapolis on the worldwide map.

“Whatever he say, we’re going to listen to it,” Rubio said. “He’s going to have a voice in the locker room, and we’ll learn a lot from him. I’m cool. I’m a winner and I’m going to do whatever it takes to win, and I think he has the same mentality. He’s tough. He’ll bring a lot of toughness, not just in games but in practice, too. That will help the young guys step up.”

That, of course, is a huge reason why Saunders brought Garnett here at this stage in his career. The team’s roster is full of impressionable youth, and Saunders is convinced Garnett will make the right impression. Indeed, Saunders laughed, saying players’ phones better be in the lockers before KG walks in pregame or there might be heck to pay. He also said that never in his career had he gotten such universally good feedback from players after a trade was made.

“Everybody knows KG’s competitiveness, his high basketball IQ, his preparation,” Saunders said. “And what he demands from his teammates to prepare to be ready to play. … It’s our hope he’ll bring that to the table. He will have a lasting influence on all our young players.”

Like Martin, Rubio knows the team’s young players are in for an attitude adjustment.

“In the locker room he’s going to have a big voice, and I think we need that,” Rubio said. “I think everyone will respect him. It’s going to be fun, I’m a big fan. It’s going to be great to watch his routines. I want to learn. He did something special in this franchise, and I want to copy him. When you talk about Timberwolves, the first name that comes to your mind is KG.”

General Manager Milt Newton offered a perfect example of the impact Garnett should have. After a home loss this season, Newton and the coaches were in their office when they heard laughter coming from the players. So they pulled some young players in and told them that losing should hurt, not be a cause for laughter.

“I guarantee you we won’t have that problem,” Newton said. “And if we do have that problem, I or Flip won’t have to be the ones to make that comment or make that message to the players.”