CHARLOTTE, N.C -- Carolina Panthers star Christian McCaffrey is signing a four-year extension, averaging $16 million per year, making him the highest-paid running back in NFL history, sources told ESPN.

Dallas Cowboys running back Ezekiel Elliott had been the NFL's highest-paid running back at $15 million per year. Jets running back Le'Veon Bell now ranks third at $14.1 million a year.

The deal includes a fifth-year option, a source told ESPN's Jeremy Fowler. Including the two years left on McCaffrey's rookie deal and the option, the deal is expected to pay out around $75 million over six years.

"I'm so excited to continue my career in Carolina," McCaffrey told ESPN on Monday. "I want to thank Mr. [David] Tepper, Marty Hurney, and Coach [Matt] Rhule for the opportunity to help lead this great franchise, and to all my teammates for their help along the way. And to Panthers fans, KEEP POUNDING!"

The extension ties McCaffrey, who won't turn 24 until June 7, to Carolina through the 2025 season. He was in the fourth year of his rookie deal, and the Panthers didn't want to enter this season with McCaffrey's future in question as Rhule rebuilds a team that finished 5-11 last season under Ron Rivera.

"He really builds to the culture you want to have within the building,'' Rhule said of the running back last week. "We want to be a serious football place. We want to be a place that is all about the game. That's who Christian McCaffrey is.''

Rhule said one of the reasons he hired LSU passing game coordinator Joe Brady as his offensive coordinator was to take full advantage of dynamic players such as McCaffrey.

"That's what Christian is,'' Rhule said. "To label him a running back, that's not respectful to him. He's a tailback/wideout. He can do it all. I'm anxious to get him out there and to continue to build this thing around him.''

McCaffrey last season became the third player in NFL history to have 1,000 yards rushing and receiving in the same season. He joined former San Francisco back Roger Craig (1985) and Hall of Famer Marshall Faulk (1999) on the elite list.

McCaffrey's deal came two weeks after general manager Marty Hurney said the organization had internal discussions on an extension. The two sides moved quickly to get the deal done after that as Carolina wanted to lock down a key piece before the draft, a league source said.

"Christian McCaffrey is a centerpiece player that you can build around,'' Rhule said. "He's going to be a special player for us.''