Martinez expects Naismith to face Chelsea
Naismith was introduced as a substitute in Everton's 3-1 victory over Swansea City in the fifth round of the FA Cup on Sunday, scoring the second goal and winning the penalty from which Leighton Baines notched the third.
However, the 27-year-old failed to see out the match after a nasty collision with Jordi Amat in the closing stages.
Fears Naismith could be set for a spell on the sidelines have been quelled by Martinez, who expects the former Rangers man to be available for selection for the trip to Stamford Bridge on Saturday to face Jose Mourinho's high-flyers.
"Stevie (Naismith) has reacted really well. It was a little bit of a concern straight away when he had that delayed concussion," he told Everton's official website.
"Two hours after the game he was fine but for the next 24 hours it's then important you're in observation and we're checking all the signs are right.
"We've done that and Stevie is perfectly well. Over the next three or four days we're going to keep an eye on how he is recovering, but I would say that Stevie will be fully fit for the weekend because he's ready now to get back to work as normal."
In a further boost, Martinez expects striker Romelu Lukaku to return for the home encounter with West Ham on March 1.
The Belgium international is unavailable to face parent club Chelsea, but Martinez believes that is beneficial as he has more time to recover from an ankle injury he sustained against Liverpool on January 28.
He added: "It helps in a way that he's not available for this weekend because this game may have been a little bit too early for him to be involved with the team.
"But now we've got nearly two weeks to make sure that he's fully fit for the next home game and that's very much a realistic target."