1 Calvin Johnson goes off. The Lions wide receiver has scored a touchdown in three straight games and has produced 100 receiving yards twice during that span. Big receivers have caused the Ravens trouble all season.
2 Penalties have impact on game. The Ravens committed a season-worst 12 penalties (including five pass-interference ones) at Green Bay on Monday. The last time the Ravens played Detroit was 2005, when they had 21 penalties (one shy of the NFL record).
3 Injuries begin to take their toll. The Ravens have lost one starter on defense for the season (cornerback Fabian Washington) and could be without two more against Detroit (safety Ed Reed and linebacker Terrell Suggs). It has gotten so bad that even kicker Billy Cundiff is dealing with a mild concussion.