And it may be a player currently completely off the radar.
After all, anyone choosing their potential England squad for the 2016 European Championships in February of that year would have had no reason to include the name of Marcus Rashford on their list of probable and possible selections.
Then came a pre-match injury to Antony Martial, a start for Rashford against Midtjylland in the Europa League and just four months later the 18-year-old was setting up Daniel Sturridge’s dramatic winner against Wales in Lens.
Rashford came out of the Euros with credit against his name, unlike many in the England squad, but an even more dramatic call-up, that of Theo Walcott for the 2006 World Cup, failed to pay off for Sven Goran Eriksson.
Aged just 17 at the time, Walcott had yet to even make a senior appearance for Arsenal when he was included in Sven’s 22.
Giving his reasons for the choice, the Swede said that Walcott’s pace was a key factor and that is why it is usually a forward player who gets the nod as a ‘wild card’ with their potential ability to change a game as a substitute.
The early contenders to fill such a role in Southgate’s squad are those players who performed well in the Under-20 World Cup, such as Ademola Lookman of Everton, his team-mate Dominic Calvert-Lewin and fellow Dominic, Solanke who has just moved to Liverpool from Chelsea.
They are all part of the England set-up already, of course, and known to the coaching staff but it may be that someone emerges from nowhere to cause the manager a selection problem in May.