Baltimore could enter, and conclude, the season without its star slot cornerback.
"Tavon [Young] has a more serious issue than we thought. He has a neck issue," Harbaugh said. "The doctors can explain it but it's a disc issue so that's a serious injury. He could be out for the remainder of the season. We'll know soon but it doesn't look good for Tavon."
Young suffered the injury in practice and did not play in Baltimore's preseason opener, per ESPN's Jamison Hensley. The cornerback returned to practice on Saturday and Sunday, but had not participated in Baltimore's last two practices.
Young has played in 31 games for Baltimore, starting in 17, recorded three interceptions, recovered four fumbles and scored two defensive touchdowns over his three-year career. Young missed the entire 2017 season with a torn ACL.
Young is not assuredly out for the season until he undergoes surgery on his injured neck. The Ravens nickelback has not decided to do so, but Harbaugh said that is the recommendation.
"There is an outside chance that you'd opt to try to see if it'll heal. But I don't think we're recommending that right now," Harbaugh said. "If he gets the procedure done, he'll be fine and good to go. That's probably the best thing to do."