Everton defender Bryan Oviedo is set to miss Saturday's Premier League trip to West Ham with a hamstring injury.
Oviedo had to come off after just 25 minutes of Sunday's 6-2 victory over Sunderland, and is unlikely to be ready until after the international break, according to Martinez.
That would rule him out until Everton's league match at home to Aston Villa on Nov. 21, although the club will have a clearer idea of the length of his absence once he has had a scan later on Tuesday.
It is a setback for Oviedo, who has suffered a number of injuries since breaking his leg during an FA Cup fourth-round victory at Stevenage in January 2014, which meant he missed the World Cup in Brazil.
Martinez told Everton's official website: "It is a sad incident, because of his injury history. Bryan has been fighting to get fit after the horrific break that he had.
"We're going to find out a bit more about the extent of the injury, but we don't feel it's anything too serious. This niggle is a setback, but it's one where after the international break, he'll be back to his best."
He managed only two league starts last season before suffering a hamstring injury that ended his campaign.
Having returned to action at the start of this season, he then missed nearly two months with knee ligament problems, and only made his latest comeback in last Tuesday's Capital One Cup victory over Norwich.
Martinez added: "It seems that when you come back from a long-term injury like that, the mechanics of your whole body suffer a little bit. That's what Bryan has been picking up, little injuries and little niggles.
"But he's such an incredibly driven individual that it will never stop him from being back on the pitch."
