Atalanta midfielder Andrea Rinaldi has died at the age of 19, the Serie A club have confirmed.
Rinaldi suffered a brain aneurysm last Friday and was taken to hospital.
Legnano, the Serie D club where the player was on loan, described the news as "a sudden and shocking tragedy, impossible even to imagine".
Club president Giovanni Munafo said: "Andrea came to training and first came to greet me. This is a memory I will carry in my heart.
"[He was] an extraordinary boy, an example for everyone. On behalf of the club, I express my deepest condolences to the family."
Rinaldi joined Atalanta's youth system at the age of 13 and won the Scudetto and Supercoppa with the Under-17 side in 2016.
"That kind smile of yours will always stay alive in the hearts of those who had the good fortune to meet you," Atalanta said in a statement.