Eto???o???s move to Sampdoria was confirmed on Tuesday and Martinez sees Arouna Kone, who is fit again after a long-term knee injury, as the player to fill his shoes.
Everton have failed to win any of their last eight games, but Martinez believes there is no need to bring in reinforcements.
He told the club’s website: “January is not the place to find solutions. Our moment of form, we want to change, but the solutions are in the squad.
“With Arouna Kone being fully fit, I see him as a replacement for Samuel’s position and it is more about trying to get the players back from injury.
“Steven Pienaar and Leon Osman have been two players missing throughout the season, which has been disappointing because they are important in the way we want to play.
“Leon played in every single game last season and we miss what he brings. So I am looking around that.???