Pele was readmitted into an intensive care unit at a hospital in Sao Paulo on Friday, but is recovering well according to his daughter.
The Brazil legend left the Albert Einstein hospital on Tuesday following successful surgery to remove a tumour in his colon earlier in September.
The 80-year-old's health appears to have deteriorated since then and the three-time World Cup winner has reportedly been readmitted to the ICU due to an acid reflux.
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Pele's daughter Kely Nascimento has confirmed he is back in hospital and has taken "two steps forward" after a "little step back".
She posted on Instagram: "Hi friends. I don't know what is going on with the rumours out there but my DMs are booming!!!
"There's already a lot of anxiety roaming the world these days and we don't want to be the reason for more. This photo was taken just now. He is wearing a vest because he is Santista and the cold in SP bothers him!
"He is recovering well and within normal range. Promise!
"He doesn't like it when I say this so please don't tell him but he is an O’Keefe gentleman. The normal recovery scenario for a man of his age, after an operation like this , is sometimes two steps forward and one step back.
"Yesterday he was tired and took a little step back. Today he took two forwards!
"I want to thank again, and always, the brilliant team here at Einstein and even more gratitude for all of the good energy that you are transmitting."
The four-time World Cup winner said in a message to fans on Instagram after leaving the ICU earlier this week that he was ready for "90 minutes, plus extra time."
Pele has suffered from hip problems for years and cannot walk unaided. In recent years he has undergone kidney and prostate procedures. In 2014 he spent time in the ICU due to a severe urinary tract infection.
His public appearances have been limited since the Coronavirus pandemic hit in 2020 and has rarely left his house near Santos since.
Pele is Brazil's all-time leading scorer with 77 goals in 92 matches.
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