Manchester United midfielder Michael Carrick has revealed he underwent a procedure to resolve an "irregular heart rhythm" after feeling unwell during September's EFL Cup tie against Burton Albion.
The 4-1 win at Old Trafford remains Carrick's only appearance for Jose Mourinho's team this season and his absence was initially attributed to a calf injury.
Reports emerged last month that Carrick had been suffering from a mystery illness and the 36-year-old issued a statement via Twitter on Friday to offer clarification over the reason for his absence.
"I just want to clear up my situation as I've had a few people asking if I'm okay and why I haven't been fit over the last couple of months," Carrick said.
"After feeling strange during the second half of the Burton game in September I underwent a series of tests.
"It turned out to be due to an irregular heart rhythm which has been fully investigated and I had a procedure called a cardiac ablation."
Here is a statement in relation to my recent fitness. Thank you. pic.twitter.com/RN3TOE9VT4— Michael Carrick (@carras16) November 24, 2017
Carrick went on to offer assurances that he is back in full training with United and targeting a return to action in the near future.
He said: "I had to build up training steadily whilst being monitored closely but I feel fine now. I would like to reassure everyone that I'm healthy and back training hard with the team.
"I'm building up my fitness and aiming to be back in contention for selection soon. Thanks for your support."
A cardiac ablation is a procedure that breaks abnormal circuits in the heart and uses either heat or freezing to destroy areas of the muscle that trigger arrhythmias.
Carrick's absence has been keenly felt by Mourinho over recent months, with fellow central midfielders Paul Pogba and Marouane Fellaini having only recently returned from their own spells on the sidelines.