assuming our starting NIs are: 
4 OLs (Greaves, new center, Penser, Neufeld) 
2 Recs (Watson, Kohlert) 
1 S (Alexander) 
  
our backup NIs would look like 
1 OL (eg. Morley) 
2 Recs (eg. T.Gudino, Brescasin) 
3 FB/RB (Volny, Pontbriand, Fitzgerald) 
  
3 DLs (Thomas, Lucas, Richardson) 
1 LB (eg. Stephan) 
3 DB (eg. Newman, Muamba, Bucknor) 
  
i think thats is not too bad for rotation especially in the D 
lot of NIs to play special teams 
the only black spot is in the LB so the other DI should be there