The 26-year-old had stayed with The Lions to recover instead of returning to Leeds United and hopes to be back by the weekend.
"Tresor picked up a knock to his thigh on international duty and we are pleased that he has chosen to stay with us for treatment rather than return to his parent club Leeds," explained Millwall physio Bobby Bacic. "Tresor is a tough character and we are confident about getting him back training soon."
However midfielder Marc Laird looks set to miss the next few games after sustaining a hamstring injury during the game at the Sixfields Stadium.
"Marc suffered a strain to his hamstring so he will be out of action for a little while," Bacic told the club's official website.