Eifert played in the first two games but spent some time on the sideline getting stretched out during last Thursday night's game. He was not at practice all week.
Eifert, 27, was one of the team's top red zone targets in 2015 and made 13 touchdown receptions. He played in only eight games last season due to a combination of back and ankle injuries. In his absence, Tyler Kroft will likely see more targets for the Bengals (0-2).
Eifert underwent offseason surgery on his back, which he admitted in July will affect him in some ways for the rest of his career. He was unable to participate in practice during organized team activities but was back by training camp.
The 2013 first-round pick is in the final year of his rookie contract with the Bengals. This will be the 28th game he has missed due to injury in his NFL career. Eifert has never completed a full season without injury.
Rookie wide receiver John Ross has also been ruled out for Week 3 with a knee injury.