It's all speculation on Earl, because he's never missed a game other than the Bucs game.
So you guys might be right, but I hope you're wrong.
Deion Sanders explained it well when asked if Earl was a huge loss, he said yes but not half as bad as losing a corner like Sherman. He said the reason schemes like the cover 2 and cover 3 were invented is to hide weak or mediocre safety play, as you can roll nickel and dime DB's into zones, as well as bracket with LB's down the middle to hide weaknesses in the safety position.
So that's my answer, after Russell the one player that it'd be catastrophic losing is Sherman.