If you really think the knee is that bad, you could just have the OLB/DE crash to the back and make the QB keep it. The risk is that if the knee is better than you think, he could take it to the house on you.
How much did they run the true read option on us last time, anyway? IIRC, Griffin only kept it a few times. If you really want him to keep it, you can shade to playing the back more.
Personally, I doubt they run it that much anyway. I suspect we see something more like what Houston runs, still with the play action and rollouts and boots, but not so much true option with Griffin reading and coming down the line.
Jason Garrett offense rank minus Tony Sparano: 18, 14, 7, 15, 15