Gareth Bale is set to become the second youngest player in Saints' history - and David McGoldrick is also in line for his Championship debut over the Easter weekend.
Left-back Bale will be just 16 years and 273 days on Saturday, and manager George Burley has revealed that the Welsh under-21 international is likely to make his debut now that Danny Higginbotham has been ruled out for the season.
Bale is a former room-mate of Theo Walcott, who was 16 years and 143 days when he became Saints' youngest ever player against Wolves on the opening day of the season.
But he is younger than Danny Wallace was when the former Manchester United winger made his Saints bow, aged 16 years and 313 days, at Old Trafford in 1980.
Like 39-goal McGoldrick, Bale has been outstanding all season for Saints' under-18s and the reserves.
Both were star performers in the team that reached the FA Youth Cup semi-final.
With Saints now virtually free of relegation worries, Burley is stepping up his planning for a Premiership promotion push for next season.
And that includes looking at some younger members of his squad.
McGoldrick and Bale, who was born in Cardiff and comes from Merthyr Tydfil, are likely to be handed their Championship debuts against Millwall at St Mary's on Monday.
A positive Burley said: "We've got two games in three days and we'll be looking maybe at other players.
"We have one or two young players there as well for the future, people like David McGoldrick and Gareth Bale.
"Both of them will probably get a run out which is good for them.
"David McGoldrick is 18 and Gareth is only 16 so we'll have to look at it - the game against Millwall may be better as a home crowd could help."
Burley will have been encouraged by the recent return to training for Kyle Critchell, another highly rated teenage left-back.
But Higginbotham's knee injury forced the Saints boss to play Alexander Ostlund out of position against Brighton on Saturday.
"Danny Higginbotham getting injured leaves us short in that department and Gareth has got a big future at the club," added Burley.
"Even though he is only 16 he has done well in the reserves and we'll see what happens against Stoke on Saturday with a view to Monday."
McGoldrick, an unused substitute in Saints' last two games, has already made his Football League debut.
He missed out on becoming Notts County's youngest ever player by just two days when he was handed his debut for his hometown club, aged just 16 years and 56 days, in January 2004.
McGoldrick failed to score in two starts and two substitute appearances for Notts County before signing for Saints.
He was given his Saints debut by Harry Redknapp in September, when he played the last ten minutes of the miserable 1-0 Carling Cup defeat at Mansfield.
But he was back at Notts Countu on loan just a few days later and failed to score in four starts and three substitute appearances for the Magpies.
He returned to St Mary's at the end of October and taking his frustration out on several under 18 and reserve team defences.
McGoldrick, who will be 19 in November, has netted 12 goals in 13 starts for the reserves as well as 27 for the under-18s, including eight in six FA Youth Cup appearances.
His goalscoring feats have also been matched by a general improvement in his game and the player himself is itching for a first team run.
"It's hard to ignore," said Burley of McGoldrick's goals. "He is playing in the reserves and still scoring and his all-round game has improved in the last few months.
"We're in a fortunate position with a number of young strikers.
"Leon Best is out on loan, Dexter Blackstock has done very well, we've also got Kenwyne Jones and then somebody like David as well."
Bale will become the 41st player used by Saints in a competitive game this season if he makes his debut.
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