Bolton defender Gary Cahill is expected to be out for the rest of the season after suffering a blood clot in his arm.
Cahill was a late withdrawal from the side that drew 0-0 with Fulham on Saturday and, while initial reports had suggested a shoulder problem, Coyle has now confirmed that the player has suffered a blood clot.
“Gary suffered a pain in his arm and it became severely swollen on the day of the game,” he said. “There was no way he could play so we took him straight off to hospital. It turns out he had a blood clot in his arm, so he is going to be out for a number of months.
“It is a severe blow for the boy but our main concern is his welfare. We have to make sure Gary is fit and well. He will miss the next few months. It might be for the rest of the season – we will hear from the specialist later.
“The clot needed to be resolved and in doing that you need the medication. It follows you can’t play. As disappointed as we are, at 24, Gary has a marvellous career ahead of him.”
Fabio Capello has previously called Cahill up to train with England, and he was considered a potential candidate to be included in the squad for South Africa.
Coyle said: ” I believe he would have made the World Cup for the summer but we have to make sure first of all he recovers from this blood clot.”