These could come in the form of a trait or just some general change.
1. When you evade or dodge an attack, your pet evades as well.
2. Your pet cannot lose more than 15% of its HP from attacks occurring within 1 second of each other.
The main purpose of these changes to is to prevent pets from being 1 shotted by stuff like Subject Alpha or Lupi. I think the first change would be better.