Last season players who picked up a fifth booking had seven days grace before a suspension came into effect but now any ban is immediate.
A Football Association spokesman confirmed: "Suspensions for five bookings now bring about an immediate suspension."
It is another setback for Villa boss Martin O'Neill who also has striker Emile Heskey (back) wide player James Milner (calf) and Craig Gardner (groin) as major doubts.
Nigel Reo-Coker is the leading candidate to fill Petrov's role.
He has not started a league game since his training ground spat with O'Neill in September but impressed as a substitute against the Hammers - his former club.
The only plus point for O'Neill is that defender Carlos Cuellar will be available to face Bolton after serving a one-game ban for his red card in the 1-1 draw with Everton at Goodison Park last weekend.