The Baltimore Ravens can still clinch a playoff berth if Pittsburgh loses at Dallas. But here's the scenario, although unlikely, in which the Ravens could miss out on the postseason:
Ravens lose last two games
Bengals tie Steelers in Week 16 and win Week 17
Steelers win Week 15 and 17
Colts win or tie any of last three games
In that scenario, the Steelers would win the AFC North and the Bengals and Colts would be the Wild Card teams. Of course, this is meaningless if the Steelers lose at Dallas.
Thanks to Jeremy Mills from ESPN Stats & Information for his help with this.