ALAMEDA, Calif. (AP) — The Las Vegas Raiders have agreed with free agent linebacker Cory Littleton on a three-year contract.

A person familiar with the contract says the sides came to agreement on the deal to give the Raiders a major upgrade at linebacker. The person spoke on condition of anonymity because the contract can't be signed until the start of the new league year on Wednesday. NFL Network reported the contract is worth up to $36 million.

Littleton is the second big free agent addition at linebacker for the Raiders, who have had a revolving door at the position in recent years. A second person said on condition of anonymity Monday that the team also agreed to a three-year deal with former Chicago linebacker Nick Kwiatkoski.

The Raiders also agreed to a one-year deal with veteran tight end Jason Witten, according to a person familiar with the deal speaking on condition of anonymity because it can't be announced until Wednesday.

The Raiders entered free agency with only one linebacker who started a game last year under contract in Marquel Lee. They have spent years trying to fill the position with mostly lower-round draft picks and bargain free agents.

Coach Jon Gruden and general manager Mike Mayock are investing heavily in the position this offseason with two major additions to open free agency.

Littleton is one of the best coverage linebackers in the league with the ability to match up with tight ends and running backs. Littleton's 26 passes defensed are the most of any linebacker in the NFL over the past three seasons, according to SportRadar.

The 26-year-old Littleton joined the Rams as an undrafted free agent out of Washington in 2016. After playing mostly on special teams his first two seasons, Littleton became a fixture on the defense in 2018. He started all 32 games the past two years with 259 tackles, 22 passes defensed, five interceptions, two forced fumbles, four fumble recoveries, 7 1/2 sacks and 15 tackles for loss.

Witten, who turns 38 in May, will team up with the coach he once replaced in the "Monday Night Football" announcing booth. Witten retired from the NFL following the 2017 season to take a job as an analyst for ESPN after Gruden left the broadcast booth to return to the Raiders.

Witten changed course a year later and returned to the Dallas Cowboys. He had 63 catches for 529 yards and four TDs last season. He has 1,215 catches for 12,977 yards and 72 TDs in 16 seasons with Dallas. He will provide depth behind starter Darren Waller on the Raiders.

___

More AP NFL: https://apnews.com/NFL and https://twitter.com/AP_NFL