To make room on the roster, the Chargers officially placed safety Adrian Phillips on injured reserve with a broken right forearm.
Henry suffered a tibia plateau fracture to his left knee during the season opener against the Indianapolis Colts, and he likely will miss four to six weeks. He has not been put on injured reserve.
With Henry out and the team moving on from Antonio Gates, the Chargers needed to add a receiving tight end to the fold. Kendricks should serve in that role, joining tight ends Virgil Green and Sean Culkin on the active roster.
Kendricks, 31, was signed by the New England Patriots before the 2019 season, but he was suspended for the first game of the season for violating the league's substance abuse policy. He then was released after being reinstated.
In July, Kendricks was sentenced to six months of probation following a 2017 incident in which he was cited for misdemeanor marijuana possession at a traffic stop. He pleaded no contest, and the charge will be dropped if he completes eight hours of community service. His one-game suspension this season was a result of the 2017 incident.