Smythe was diagnosed with a torn Achilles tendon following an MRI on Monday and will require season-ending surgery, Ian Rapoport of NFL Network reports.
The Ravens had been concerned that Smythe ruptured his Achilles during Sunday's win over the Titans, and the MRI ended up confirming the team's fears. The 31-year-old tight end suited up for each of the Ravens' first four games, serving mainly as a blocker while contributing a four-yard reception on two targets. He'll be ticketed for free agency in the spring after signing a one-year, $3 million deal with Baltimore in the offseason.