Jamie Skinner, 13, was playing for Edinburgh-based Tynecastle FC against Spartans FC when he collapsed on the Saughton Astro pitch in the city.
A statement from Heart of Midlothian Youth Development Committee said: "Jamie was a talented and athletic young footballer who was a member of Hearts U14 squad.
"Our thoughts are with Jamie's family and friends at this sad time."
Meanwhile, a statement released by Hibernian FC confirmed the death of David Paul.
It said: "It is with great sorrow that Hibernian FC today confirms the sad death of youth player David Paul, 18.
"David, who could play in midfield or in attack, passed away in the early hours of today at his home in Edinburgh. There are no suspicious circumstances surrounding David's untimely death.
Chairman Rod Petrie said: "Everyone at the club is deeply affected by this."