The 31 year old striker had a difficult time for the Latics last season, however a number of Championship clubs are said to be chasing his signature.
Of those clubs, Roy Keane's Ipswich are said to be interested and a fee of £1 million has been touted.
Speaking after the Latics 3-1 friendly win over Dundee United, Martinez said: "It's not the first time that a few clubs have been in for one of our players. We'll see what happens.
"It's fair to say there is strong interest there from Ipswich Town, and a few other clubs have also asked us about Jason.
"It's just a case now of sitting down with all the parties and working out what is the best move for Wigan Athletic."
It is believed that Ipswich et al believe that Scotland can refind his scoring boots in the Championship.