For Ireland, Roy Keane was always number 6 (except for one game against Lithuania in 1997, when he wore 4). This was a good fit as he had worn it at Nottingham Forest too, though his debut against Liverpool in 1990 had come wearing 7 as Brian Clough chose him on the right of midfield.
Keane signed for Manchester United in the summer of 1993, when squad numbers were introduced for the first time. For the Charity Shield, United stayed 1-11 and Keane was 9, though when the Premier League numbers were announced he was 16, with the first-choice players in the 92-93 league win retaining their numbers.
That meant that captain Bryan Robson, for so long the number 7, had to be content with 12, with Eric Cantona now 7. When Cantona retired at the end of 1996-97, he was replaced by Teddy Sheringham, who always preferred 10, and David Beckham moved from 10 to 7 to accommodate him.
According to Keane’s new autobiography, The Second Half, it could have been him taking over 7 when Cantona left. How different might things be?
Squad Numbers Blog 