Robbie Brady played at left-back for United in the DHL tour game against AmaZulu.
If he makes a senior appearance for the Reds next season, he will become the 11th Republic of Ireland player to be selected by Sir Alex Ferguson since the boss took charge of the club in 1986.
So our question was simply name the other 10. Please note we were not counting Michael Keane, who represented the country at youth level but has since switched to turn out for England.
The answers are in the black box. Look out for another poser next Thursday.
More United-based trivia questions: Old Trafford penalties | England's seven Reds | Alan Hardaker Trophy winners | Scored against United | United stars at European Championship | Goals for England | The name game | Non-appearance at finals