The 26-year-old, on loan from League Two rivals Crewe, was forced off midway through the first half of the 4-1 defeat at Adams Park on Tuesday night.
Boss Paul Peschisolido feared the worst immediately after the game and, following tests on Zola, the Canadian's fears have been realised.
He said: "He will be out for four to six weeks, which is a massive blow for us at this stage of the season."
Source: PA
