The 23 year old has impressed at Everton since joining the club from Wigan in the summer to be reunited with Martinez.
"James is one of those players you sometimes don't appreciate but he's always there making sure the team has the right balance and what it needs," Martinez told the Liverpool Echo.
"He allows others to shine.
"He can adapt to different situations during a game when you need him to because of the tactical awareness that he has.
"At the weekend you saw that influence in the manner that we were able to get men forward, and give us the momentum to make it hard for Villa to keep a clean sheet."
"It is that maturity and wealth of experience which make him such a valuable player, added Martinez.
"James never plays according to his age because of the incredible amount of experience he already has at 23."
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