"He's ready to go,'' Harbaugh said. "He's going to play in this game and he should be full speed.''
It's uncertain how much Lewis -- who has missed the last 10 games since suffering the injury on Oct. 14 -- will play.
It's possible that Sunday could be the final game of Lewis' storied career. The two-time defensive player of the year and former Super Bowl MVP announced Wednesday that he is retiring after this season.
Sunday will also likely be Lewis' final game in Baltimore even if the Ravens win because of their No. 4 seed entering the playoffs. He is also close to signing a multiyear contract with ESPN to join the network as an NFL analyst, according to an SI.com report.
Lewis, 37, returned to practice on Dec. 5. For him to be eligible for the playoffs, the Ravens added him to the active roster later in the month.
Information from The Associated Press was used in this report.