BEREA, Ohio -- A source revealed to ESPN that the Cleveland Browns and Nick Chubb, star running back, have reached an agreement for a three-year extension of their $36.6 million contract.Chubb's guaranteed money of $20 million is the seventh highest in the league for running backs. At 29 he will be an unrestricted free agent.The backbone of Cleveland's offense for the past two seasons has been Chubb, who averaged 5.25 yards per carry over that time. He was 47 yards away from Derrick Henry, who won the rushing title in 2019. Chubb was injured in his knee last season and missed four games. However, he finished seventh in the league with 1,070 yards rushing.Chubb proved to be a top closer in the NFL, averaging more than 10 yards per carries in the fourth quarter last season.Chubb made one of the most important plays in Cleveland's 26-year-old playoff win. He took a screen pass 40 yard for a fourth quarter touchdown that propelled the Browns to the victory in Pittsburgh, 48-37.Cleveland selected Chubb from Georgia in the second round 2018 NFL draft. He was about to enter the final season of his rookie contract.Andrew Berry, general manager, said that he knew the love we share for Chubb as players and people when he was asked about a possible extension. He has done that the entire time he was here. That is something we all see every day, and it's something you can see externally.The Browns granted Kareem Hunt, Chubb's backfield partner, a two-year extension of $13.25 million. Hunt will remain under contract with Cleveland until the 2022 season.