Cassel is out 2-4 weeks with an MCL sprain after the hit he received from 300 pounder Brandon Mebane of Seattle.
If he is you fantasy starter time to scramble and find a backup. If he is your back up and you have a bye in the first 5 weeks, time to find another backup. Chad Pennington finished 9th last year among Quarterbacks and is available in plenty of ten team leagues. Jason Campbell, Joe Flacco and Shaun Hill could also be legitimate fantasy backups or one week fill ins.