Ian Rapoport and Jane Slater of NFL Network reported the news, noting "roughly half" of the deal is guaranteed. Elliott's full contract is $103 million over eight years. The Cowboys later confirmed the agreement.
Todd Archer of ESPN reported "the plan" is for Elliott to be present at Wednesday's practice.
The 24-year-old had two years remaining on his deal after the Cowboys picked up his fifth-year option earlier this offseason. He has not only arguably been the NFL's best running back since being taken with the No. 4 pick in the 2016 draft, but he is also one of the most productive in league history.
Only Jim Brown (104.3) has averaged more rushing yards per game than Elliott (101.2) has through his first three NFL seasons. He is one of 13 players in NFL history to rush for 4,000 yards in his first three seasons, doing so in fewer carries than anyone on the list.
Cowboys head coach Jason Garrett told reporters:
"Well, Zeke's a great football player, and good things happen when he has the ball in his hands, but we understand the pounding that he takes. He's a focal point of every defense that we play against. We like to hand him the ball; we like to throw him the ball. Again, a lot of positive things happen for our team when we do that.
"But we recognize the workload, and we just have to make sure that we have good alternatives to that going forward, whether it's in-house or somewhere else."
Elliott's workload included a massive uptick in the passing game last season. After recording just 58 receptions his first two years, he caught 77 passes for 567 yards and three touchdowns in 2018. He was named to the Pro Bowl and All-Pro teams for the second time in his career.
The Cowboys could have followed the Pittsburgh Steelers' model with Le'Veon Bell by having him play out his contract before franchising him twice. That would have given them the bulk of Elliott's prime without having any long-term financial obligations.
Bell, considered the NFL's best all-around back before sitting out the 2018 season, got a four-year, $52.5 million contract from the New York Jets. Meanwhile, the Los Angeles Rams' Todd Gurley signed a four-year extension in 2018 worth up to $60 million, with $45 million guaranteed.
With the contract stuff taken care of, Elliott and Co. can now focus on the division-rival New York Giants in Week 1 on Sunday.