Rangers have been given a boost with Dado Prso not being called up for Croatia's friendly with Brazil.
Prso was Rangers leading scorer last season
Croatia coach Zlatko Kranjcar has relented to appeals from Ibrox not to include the striker as he prepares for Saturday's Old Firm clash with Celtic.
"We were not trying to pull a flanker with Croatia," manager Alex McLeish told the club website.
"Dado has told them that if they spare him for friendly games then he will be fit and fresh for World Cup games."
Prso, who was on target during Sunday's 3-2 loss at Aberdeen, has been struggling with an ankle injury and recently revealed his concern about an old knee problem flaring up.
"In terms of sharpness, it is the right thing to do," added McLeish.
"He wants to play in the World Cup and if he was forced to play in friendlies then I think his sharpness could diminish for both club and country."