Only if there will be a definite collision within (say) twenty years. Otherwise perturbation of asteroid orbits is just as likely to produce a collision with E

Only if there will be a definite collision within (say) twenty years. Otherwise perturbation of asteroid orbits is just as likely to produce a collision with Earth than to prevent a collision with Earth. The only way to completely prevent a collision between the Earth and an asteroid is to completely remove the asteroid. And good luck with succeeding in that.