The 30-year-old, who is believed to have suffered with the injury for the majority of last season, had initially been expected to return in October.
Dalton told the club's official website: "He is on target but will be around four months before he can start playing again.
"At the moment he is only doing light work due to the brace. He will be doing light bike work and arm weights during the period as we continue to assess his progress."
McCombe's return date has been set at early 2014.