The midfielder suffered a fractured shin during the Latics' 3-0 defeat to Liverpool last weekend.
It was feared that Watson would be sidelined for a prolonged period of time, but Wigan announced on Monday that they expected him back 'in the New Year'.
Martinez has now offered a further update, with it possible that he could welcome the 27-year-old back into his plans inside three months.
"After the plaster comes off in the New Year, you're then looking at a block of about three or four weeks to get the full fitness back - which is around the beginning of February," he said in the Wigan Evening Post.
Meanwhile, Martinez has also been looking ahead to Wigan's Premier League clash with Reading on Saturday, a game he considers to be crucial to the Latics' top-flight cause.
"It's a massive game, because all of your home games in the Premier League come into that category," he said.
"Every game at the DW has been very exciting, although we haven't managed to pick up as many points as we have probably deserved."
He added: "Reading will present a completely different challenge to the ones we have faced.
"They will be coming here on a massive high after beating Everton, and will be full of confidence because of that.
"We are coming in after two defeats, but we are at home and we have to be prepared to perform as well as we can. It's a game where we can't afford to be below our best."