Eifert reportedly is consulting with doctors in Los Angeles to determine if he should have micro-disk surgery, which would sideline him for four to six months. The surgical procedure on his back would be the third for the 6-foot-6, 255-pounder.
Eifert appeared to sustain the injury during Cincinnati's 13-9 loss to the Houston Texans on Sept. 14.
The 27-year-old Eifert was selected to the Pro Bowl after reeling in 13 touchdown passes during the 2015 season. He has just four catches for 46 yards in two games this season.
Eifert has 127 receptions for 1,537 yards and 20 touchdowns in 39 career games since being selected with a first-round pick (21st overall) in the 2013 draft out of Notre Dame.
Tyler Kroft has stepped into the lead tight end role with Eifert sidelined. Kroft has 14 catches for 139 yards and two touchdowns this season.