Along with a Team Defense category, there is also a Team Offense category. Thinking of entering this in one of my leagues: 1/2 point per first down, 5 points for a win. Minus 5 points for a shutout. And, 1 pt. for 10 to 19 points made, 2 pts. for 20-29 pts., 3 pts for 30-39 pts., and so on.

Another idea is to come up with a completely different format whereby you draft an entire team for each position. In that way, if your QB gets injured, you automatically are filled in with his backup. You could draft all RBs of any team, WRs of any team, TEs, Ks, and, of course, team Defense. It would not matter if this were an 8-member league or a 12-member league. They may even draft the same category, due to so many options, no two teams would have the exact format going into that week. I had my own league one year, and I put this to the test; I did all the stats, and it worked out flawlessly. Mind you, it was a lot of work for me to do everything, and the following year I had to give it up as it was too time-consuming for one individual. Give it a go, you have nothing to lose.