The deal is for one-year, according to Kendricks' agent, David Canter.
The 6-foot-3, 250-pound Kendricks, who has played for the Rams (2011-16) and Packers (2017-18), adds another veteran option at a position where the Patriots are transitioning without the retired Rob Gronkowski.
Kendricks has totaled 241 catches for 2,505 yards and 19 touchdowns over his career. Last season, he played in all 16 regular-season games for the Packers, amassing 19 receptions for 170 yards and one touchdown.
The Patriots are thin at tight end, with four-year veteran Matt LaCosse -- who had a career-high 24 receptions last season with the Denver Broncos -- among those atop the depth chart. Veteran Benjamin Watson, 38, is also in the mix but will serve a four-game NFL suspension to open the season.
Kendricks, who entered the NFL as a second-round draft choice in 2011, played in college at Wisconsin under Bret Bielema, who is in his second season on the Patriots' coaching staff.
He also played under Patriots offensive coordinator Josh McDaniels as a rookie with the Rams in 2011.