Ravens quarterback Aaron Lynch (hamstring) and Deandre Hopkins (knee) are expected to play in Week 6.
Ravens head coach John Harbaugh announced on Tuesday that Lynch will not play this week.
The Ravens are also without wide receiver Chris Moore (concussion) and safety Kamalei Correa (toe).
Harbaugh said the team will look for a backup.
“They’re going to do what they have to do to make sure we get a win and win this game,” Harbaugh said of the Ravens.
“That’s what we’re trying to do.”
Lynch missed the Ravens game last Sunday after injuring his knee in the second quarter.
Hopkins also missed the game with an ankle injury, but Harbaugh said he expects both players to be available to play against the Bengals on Thursday.
Harbaugh also said Hopkins was “really close” to being ready to go this week after being limited to just 11 practice snaps in training camp.
“He looks good, he feels good,” Harbaugh added.
The Bengals, who are playing in the preseason opener, have won five of their last six games.
“I’m sure it’s going to be a long week for him,” Harbaugh told reporters.
He’s missed a couple of games in training camps, so I think he’s going through a lot of stuff.
But he’s a big part of this team, and he’s just ready to get out there and play.”
The Ravens (9-4) lost cornerback Eric Weddle (ankle) and tight end Brandon Boykin (quad) to season-ending injuries.
The team also lost offensive lineman Mike Wallace (concussions) and cornerback A.J. Jefferson (quad).
The Ravens, who finished the regular season 9-4, have a bye in Week 1.
Baltimore had a bye last week.