The 29-year-old didn't make an appearance for the Raiders in 2020 after undergoing surgery for a torn labrum last September. Prior to that, he had been a solid secondary passing option for Las Vegas and the Los Angeles Chargers.
Williams caught 69 passes for 1,059 yards and seven touchdowns in 2016. That's a bit of an outlier because he proceeded to average 42 receptions for roughly 677 yards and five scores over the next three years.
His presence could be vital in Detroit with leading receiver Marvin Jones and 2019 Pro Bowler Kenny Golladay due to become free agents. According to NFL Network's Ian Rapoport, Golladay is an option to get franchise-tagged, which still leaves a big question mark around Jones.
By going to the Lions, Williams will reunite with offensive coordinator Anthony Lynn, his coach on the Chargers in 2017 and 2018. That continuity could help him make an easier transition into a new offense.
Because of his shoulder injury, Williams carries an obvious level of risk heading into 2021. Given the team's clear need for depth at wideout, handing him a one-year contract is a sensible gamble for Detroit.