The midfielder fractured his toe in January's FA Cup victory over QPR but, despite being expected to miss six weeks of action, made his return in the derby defeat to Liverpool later that month.
Martinez admitted he made a mistake in bringing the 20-year-old back to action too soon, adding that he should not have started him in the 2-1 win over Aston Villa a fortnight ago - a game in which he was withdrawn at halftime.
"Ross is so eager to play and to be available that I brought him back too early," Martinez said.
"Especially against Aston Villa, when you come back you get through the adrenaline, it's when you need to rest from that first game and against Aston Villa at home it was too early to start the game.
"We need to make sure he is fully recovered and ready to have a massive role for us this season.
"Ross is a young man who can get through anything and that's why you have to be careful. He'll never be conscious of feeling any pain, but Ross is going to be vital and we need to make sure we use him wisely."
Martinez welcomes former side Swansea City to Goodison Park in the FA Cup on Sunday, having won the competition with Wigan Athletic last season.
The Spaniard tasted disappointment after clinching the trophy as Wigan were relegated, and Martinez is pleased the final comes after the conclusion of the Premier League this time around.
"I think the FA Cup final should always be the final game of the season," he added. "The longer you stay in a cup the better momentum you can carry.
"It is [set up better this year] yes, you shouldn't get punished for playing in the FA Cup final.
"I really think that's the right thing for everyone involved in both competitions."