CHARLOTTE, N.C. -- Hornets coach Steve Clifford says he can rattle off a dozen reasons the Hornets gave small forward Michael Kidd-Gilchrist a big contract extension.

But in Clifford's mind it all came down to one basic thought: "When he's on the floor, we play well; when he's not on the floor, we don't."

The numbers bear that out.

The Hornets were 62-55 with Kidd-Gilchrist in the starting lineup the past two seasons and 14-33 without him.

"As much as anybody that we have had in the two years I've been here, he's been the guy that we can't play well without for any long period of time," Clifford said.

The deal is worth $52 million over four years with a player option in Year 4, a person familiar with the situation told The Associated Press. The person spoke on condition of anonymity because the team did not publicly disclose contract details.

Kidd-Gilchrist agreed to the contract on Monday and signed it on Wednesday.

During an emotional news conference in which he was flanked by family, friends and former shooting coach Mark Price, Kidd-Gilchrist said one of the main reasons he chose to re-sign with Charlotte -- instead of testing the restricted-free-agent market next July -- was to continue playing with point guard Kemba Walker.

The 21-year-old also likes his situation in Charlotte.

"Why wait? I'm learning from the best," Kidd-Gilchrist said, referring to playing for owner Michael Jordan, Clifford and assistant coach Patrick Ewing. "I don't do this for the money."

Defense continues to be his forte.

Last season, Kidd-Gilchrist posted a net differential of plus-10.8 points per 100 possessions, the largest differential of any Hornets player. Charlotte was a plus-3.1 with him on the court as opposed to minus-7.7 with him off the court. He averaged 10.9 points per game last season and led NBA small forwards in rebounds per game with 7.6.

"His motor is different," Walker said. "The type of player he is, you have to have him on the court. We need him on the court every single night. When he's out there, your chance of winning is definitely higher -- definitely."

Kidd-Gilchrist talked last season about wanting to become the best defensive player in the NBA -- and he said that goal hasn't changed.

"Aim for the stars, you'll probably land on the moon," Kidd-Gilchrist said. "I have confidence in myself."

General manager Rich Cho called Kidd-Gilchrist one of the hardest workers on the team and "embodies everything we want in a Hornet."

"He's a high-character person who plays both ends of the floor," Cho said. "He's a great competitor and teammate. We feel like MKG is just scratching the surface of what he can be as a player."

Kidd-Gilchrist became emotional as he looked into the eyes of his stepfather, Vincent Richardson, sitting in the front row at the news conference.

"I owe you a ton," Kidd-Gilchrist said. "I owe you everything, honestly. There were tough times when I didn't like you at all, but I just realized the other day that I would not be here without you."