LONDON: Bolton midfielder Fabrice Muamba has been told he needs more heart surgery - increasing fears he may never play again, the Daily Mirror reported.
Muamba's heart stopped for 78 minutes during a match at Tottenham.
He is monitored daily and has been slowly building his fitness levels by jogging and playing tennis in the hope of restarting his career.
But Pedro Brugada, a leading cardiologist based in Belgium, told Fabrice, 24, he needed another operation after a recent visit.
"Fabrice wants to resume his career but the number one priority has got to be his health," said a source.
"That is all those closest to him are concerned about."
Muamba had a cardiac arrest on the pitch during an FA Cup tie on March 17 and was discharged from hospital a month later.
He has a device implanted in his chest that will restart his heart if it stops again.
Earlier this month Muamba said he had not ruled out the possibility of returning to play professional football.
"I am happy to be here and the fact is I continue to feel fine. I am improving slowly but surely," he told AS.
"At the moment I am not doing exercise, I am just enjoying life and travelling. It is a great privilege to be able to live with the assistance of a respiratory machine or something like that. It is fantastic.
"I am making small steps every day. I am still being medicated and we will see what happens. I have to co-ordinate with my doctor and see what he says but I'll never say never." said the former England Under-21 player.