Cahill was back in hospital yesterday having further checks on the other side of his body, which thankfully for the former Aston Villa man turned out to be negative.
Although Coyle stressed he never actually said Cahill would miss the remainder of the campaign, the Scot did admit it was a logical conclusion to draw given the season only has three months remaining.
But, whilst there is any hope, Coyle has vowed to explore all avenues to give Cahill a chance of being picked in Fabio Capello's squad for South Africa 2010.
"I will leave no stone uncovered to make sure we can do anything to help him," said Coyle after Tuesday night's 2-0 defeat at Manchester City.
"I never said he was out for the season. I said he would be out for a number of months - there are only three months left so maybe it is a fair assessment.
"I would love to think there was a glimmer of hope that he would be back; for us because of the position we are in and also for his personal goal of reaching the World Cup finals. He was capable of achieving that."