Didier Drogba why? John Terry Ouch and what a poorly officiated match

When Didier Drgoba slapped Vidic i wondered who would have to take his place during penalties? You would assume John Terry would not have been the fifth shooter. Not to be presumptuous but it seems Drogba would have been 5th or lower. But as he walked off the field i thought of Zidane and wondered could Chelsea survive such an expulsion.