Well I think that you need lvl2 doctor (or better if you rally care) anyway. It's not that costy - and this is really about point of view because salaries of players differ much at different levels. Injuries happen to teams with more players on roster too and it is players of the main rotation are probable victims, there is just a hope you have sufficient depth (and I think you can have that depth with 10 players too - depends on toughness of oposition, I guess I'll see next year).