Joe Flacco has been ruled inactive after missing practice all week with a hip injury. Robert Griffin III will serve as the backup for the Ravens (4-5) in their game against the Bengals (5-4) despite receiving substantial work with the first-team offense Thursday as Jackson missed practice with a stomach ailment.
Jackson was the 2016 Heisman Trophy winner and the Ravens' first-round pick (No. 32 overall) out of Louisville. The 21-year-old completed 7 of 12 passes for 87 yards and a touchdown, in addition to rushing 28 times for 139 yards and another score.
The versatile Jackson has played 86 offensive snaps in 2018. His only extended time at quarterback, however, came in mop-up duty in a season-opening rout of the Buffalo Bills.
Flacco walked gingerly into M&T Bank Stadium on Sunday after sustaining the injury two weeks ago against the Pittsburgh Steelers. The 33-year-old remained in the game and completed 23 of 37 passes for 206 yards.
The 28-year-old Griffin has played 42 games in his NFL career with the Washington Redskins and Cleveland Browns, passing for 8,983 yards and 42 touchdowns with 26 interceptions. He has not been active for a game this season.