He will undergo an operation this week and we wish him well.
"Martin is our captain and our leader, he epitomises everything we are about," boss Paulo Sousa told the club's official website.
"We have lost him as a player, but we will not lose him as a personality because he is a huge character around the club and I will continue to involve him as much as possible.
"He is a player I hold in extremely high regard and we will be doing everything we can to get him back to full fitness as soon as possible."