The Croatia international scored twice and hit the crossbar with a chipped penalty in Saturday's 4-0 home win over Queens Park Rangers, which sent Everton into the fourth round of the FA Cup.
Jelavic's goals were his first since March 16, with the striker having found game time hard to come by this season due to the impressive form of Chelsea loanee Romelu Lukaku.
After the game, Martinez outlined his desire to retain the services of Jelavic, while acknowledging the player's need to feature frequently in a World Cup year.
"I don't want to sell 'Jela'," he said.
"But I understand it's a key moment for him. If the World Cup wasn't this summer, this wouldn't be discussed.
"I thought his performance was very good. He is frustrated he didn't get the hat-trick and he deserved to.
"He hadn't done that (a chipped penalty) in training before. He executes penalties very well, but the chip showed confidence."
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