“I will operate on him. It’s a routine operation, he’s lucid,” said Leopoldo Luque.
World Cup winner Maradona, 60, was taken to hospital on Monday for a series of tests after feeling unwell.
A scan revealed the blood clot, which Argentine media are speculating was the result of a blow to the head.
Earlier in the day, Luque claimed Maradona was feeling “much better and eager to leave” hospital but insisted that the Gimnasia Y Esgrima coach was suffering from anemia — a lack of iron in his system — and dehydration.
Luque said it has left him feeling “very weak, very tired.” After further tests, he was diagnosed with a blood clot.
He is due to be transferred from a hospital in La Plata, 60 kilometers south of Buenos Aires, to a specialist clinic in the capital.
Luque had earlier suggested Maradona’s lifestyle had contributed to his condition.
“He’s an elderly patient with many pressures in his life. It’s a time when we must help him. It’s very difficult to be Maradona,” Luque said of the star, who celebrated his 60th birthday on Friday.
The doctor ruled out any link to the coronavirus pandemic, which is ravaging the South American country, much of it still under confinement.
Maradona, who has a history of drug and alcohol abuse and poor health, is considered at high risk of coronavirus complications should he be infected.
Last week he began self-isolation for the second time after a bodyguard displayed coronavirus symptoms, though he later tested negative.
He joined his players briefly at the club’s training ground on his birthday but had obvious difficulty walking and had to be helped away by his assistants after staying only 30 minutes.
“It breaks my heart to see him like this,” one of his daughters, Giannina, tweeted the next day.
He has suffered two heart attacks in the past and contracted hepatitis.
He has difficulty retaining iron due to a gastric bypass surgery he underwent in 2005 to lose 50 kilograms, leaving him prone to anemia, Luque said.
Though he has recovered from a well-documented addiction to hard drugs, Maradona takes medication in the form of tranquilizers and anxiolytics.
“With a patient on medication, there are times when hospitalization serves to adjust that medication. That’s good,” said Luque.
Gimnasia fans flocked to the La Plata clinic to leave messages of support for the ailing icon.
“What he needs most is the support of the people,” Luque said.
Alongside Brazil’s Pele, who turned 80 last month, Maradona is widely regarded as one of the greatest players of all time.