Haula was injured Nov. 6 against the Toronto Maple Leafs. McPhee said the surgery took place "a couple of weeks" after Haula was hurt.
"It wasn't an ACL, as some people reported. It's not an ACL," McPhee said. "It's just an atypical injury for hockey."
It's not known how long Haula will be out.
The 27-year-old has two goals and five assists in 15 games this season.