After missing the opening month due to Achilles problems, Judd lasted just six minutes when he was substituted in the third term.
The former skipper said the injury was down to bad luck and had nothing to do with his limited preparation for the match.
"I was really well conditioned, had done a heap of running and a heap of leg strength work so there was no issue with my conditioning," he said.
"I just got pushed by accident into a position that hamstrings can't tolerate, so it wouldn't have mattered if I trained for 50 weeks or six weeks, it wouldn't have changed the outcome."
He is expected to return in Round 10.
Ed Curnow is facing a similar stint on the sidelines after he suffered a fractured fibula in his right leg when he collided with the post during the final quarter.
No surgery will be required, but he will be out for at least six weeks.
In another blow, Tom Bell will miss a month due to a fractured finger.