The deal is worth up to $37.5 million with $12.5 million guaranteed, according to NFL Network's Ian Rapoport.
After the 2019 season, it was reported that Whitworth would hold off retirement in order to stay with the Rams. The 38-year-old spent the past three years with the team, which included an appearance in Super Bowl LIII.
The Rams' offensive line dropped off in 2019 after playing a key role in the Super Bowl appearance, but Whitworth was still considered a pillar to build around in the short term.
Whitworth was a Pro Bowler and a first-team All-Pro as recently as the 2017 season. Overall, he's made four Pro Bowls and has been named a first-team All-Pro on two occasions.