Donnarumma is training alongside Gianluigi Buffon while on duty with Italy, and Amelia has tipped him to succeed the Juventus player when he retires.
England captain Wayne Rooney has confirmed that the 2018 World Cup in Russia could be his last act in international football.
Keane, 36, told O'Neill, the coaching staff and his teammates he was retiring from international football after this summer's Euro 2016.
Leicester City goalkeeper Kasper Schmeichel is confident of a quick return after undergoing a hernia operation on Monday.
Amid speculation that he would be leaving PSG for Juve, Matuidi has been named on the bench in each of the French champions' three Ligue 1 matches.