What did dict.cc say that has to do with RG3? I don't understand.
'Save yourself' is not right in the context of being post-operative. A closer verb might be 'spare yourself,' but even that is not as idiomatic to my ears as just 'take it easy,' 'don't do too much too soon,' which is what I would suggest here.
'Save yourself' could be right in some contexts in sports, meaning to save one's energy and strength for later in the game or in a tournament, not to expend too much effort too soon. But there, a more idiomatic verb might be 'pace yourself' or, indeed, 'save your energy/strength.'
Just looking at 'save yourself,' without context, makes me think of retten, like in an accident at sea where it's every man for himself (or less sexistly, everyone for themself). 'The boat is sinking! Save yourself, I can't hold on to you!'
Another context occasionally seen is virginity: 'He doesn't believe in premarital sex. He's saving himself for marriage.'