Kai at Stud

We have been asked about using Kai as a stud, the thing that worries me at the moment is he is not at his best ! Recently, we have had to take him to our vets as he has pulled a muscle in BOTH back legs. Now, altho he is getting better (Only because we have had to crate him for long periods to stop him running around) he is still limping on one of his back legs so now I am unsure if I can allow him to Stud