Everton will be without Lacina Traore for ‘weeks rather than months’.
The striker, on loan from Monaco, pulled up in the warm-up before Saturday’s game against Chelsea with a hamstring problem.
Martinez told evertontv: “It is going to take a long period of time, which at this stage of the season will be a big miss. It will be weeks rather than months.
“It’s a really disappointing outcome. He was ready and had been working really hard since he arrived at the club. Starting the game at Chelsea was the next target after Swansea and for him to pull his hamstring in the last action of the warm-up was a really disappointing moment.
“We are a little bit concerned. We are working with his parent club and making sure we get the right diagnosis. Lacina was really down after and we need to support him. We will find out over the next 48 hours how we will treat the injury.”
Indeed, the nature of the injury means there is no scope for the player to be rushed back.
“It is a soft tissue injury in the hamstring very similar to a previous injury he had," Martinez explained.
“With these sorts of injuries, similar to the injury Gerard Deulofeu picked up before Christmas, the soft tissue is an area which needs to be well healed.”
The Traore injury setback has been offset by he impending return of Romelu Lukaku from an ankle problem.
And Martinez added: “Romelu has been working really well and he is looking fresh and ready. We are all very excited to see him back enjoying his football with really top energy levels.”
To see if Lukaku returns to action at Goodison against West Ham on Saturday, secure your tickets here.