The French international joined tLeigh midway through last season for a nominal fee from Catalans Dragons and made five first-team appearances in 2015.
The decision was reached after he met with head coach Neil Jukes.
“It is always difficult talking to players with a view to them leaving the Club and it something I have had to do on a couple of occasions recently. It is the part of the job I least enjoy,” Leigh owner Derek Beaumont.
“As a club we believe in being honest with individuals and always act in their best interests. Neil has spoken to Mathias and outlined that he feels his opportunities will be limited.
“Mathias has his wife and young son with him and they are expecting their second child so it would be inappropriate to keep him over here in these circumstances.
“Mathias goes with the best wishes of everyone connected with the club.
“It is a shame we have not seen more of him and he has struggled with injuries during his time with us.
“It has been great to have him around the Club and he has certainly contributed to the fun environment we try to create and has been a very popular member of the squad.”