Young hurt his neck in practice last weekend, and he didn't play in the second preseason game. The expected loss of Young is a big hit to one of the best secondaries in the NFL.
"Tavon has a more serious issue than we thought," Harbaugh said. "He has a neck issue. It's a disk issue. 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 became the NFL's highest-paid nickelback in February, when he signed a three-year, $25.8 million deal that included a $10 million signing bonus.
A fourth-round pick in 2016, Young stepped up as a difference-maker last season. He scored two touchdowns off fumble recoveries, becoming one of four players to score multiple defensive touchdowns in 2018. His 62-yard touchdown sealed a 22-10 upset of the Los Angeles Chargers in Week 16.
Harbaugh said there is an "outside chance" that doctors will consider seeing if Young's injury will heal without surgery, but that's not what is currently being recommended.
"I think in his best interest -- and that's always the first consideration -- is his long-term well-being," Harbaugh said. "If he gets the procedure done, he'll be fine and good to go. That's probably the best thing to do."
What the Ravens are going to miss is Young's playmaking ability. It's the reason why Baltimore made it a priority to sign Young, 25, to an extension this offseason.
"We would rather have Tavon than not have him," Harbaugh said. "But we are blessed at that position with some depth."
This is the latest injury for Young, who is in danger of missing his second full season in three years. In 2017, he tore his ACL in June and was sidelined the rest of the season.
Last season, Young battled a sports hernia for nearly half the season and didn't play in the wild-card playoff loss to the Chargers. He underwent surgery after the season.
"Tavon is a huge part of this defense," safety Tony Jefferson said. "That's just a tough situation."