The 28-year old was the subject of a bid from Manchester United this summer, the eventual destination of team-mate Marouane Fellaini, but he will remain at Goodison Park until January at least, where he has two years remaining on his current deal.
Martinez, who departed Baines' former club Wigan Athletic at the end of last season, thinks that the closure of the transfer window signals the right time to begin negotiations with the England international.
"When the window is open I think it's the wrong time to speak about those things and so we hadn't discussed it," he told reporters.
"But now the window is closed, we are going to look into all the players in the squad and see where their contracts are up to.
"Then, individually, we will look to address that.
"It would just have created more instability if we had done that while the window was open."