Eifert dislocated his elbow in Sunday's victory over the Baltimore Ravens after making a catch late in the first quarter. He had three catches for 37 yards before leaving the game.
The tight end will miss a minimum of eight weeks, eligible to return for the Bengals' Nov. 16 game against the New Orleans Saints at the earliest.
Eifert was the Bengals' first-round draft pick in 2013. Last season, the 24-year-old played in 15 games for Cincinnati, catching 39 passes for 445 yards and two touchdowns.
- Sarah Barshop