Wales are set to face Georgia and Ireland on October 6 and 9 respectively in the 2018 World Cup qualifiers.
Long's return to fitness will be a huge boost to Martin O'Neill who has beefed up his attacking options for these two pivotal games by retaining Sean Maguire, Scott Hogan and Aiden O'Brien in his final squad.
It remains to be seen when he will return to Spain for treatment, with reports suggesting he could remain in Wales and attend Monday's clash with Ireland.
The Welsh rely heavily on Bale; the Real Madrid star has scored four times in seven qualifying games, and has 28 goals in 68 appearances for his country. He, along with Joe Allen, Joe Ledley and other players, know what it's all about.
The 17-year-old winger played five Premier League games last season, but has yet to feature in the current campaign.
He said: "Aaron will have a job to do in the team which he will do as he always does".
It's as close to must-win as a game gets for Wales, who now find themselves out of the running amongst second place sides from nine groups vying for eight playoff places.
However, before they do that the Welsh still need to beat both Ireland and Georgia, to secure their second place spot, which could be tricky without Gareth Bale.
Northern Ireland have nearly certainly guaranteed a play-off spot in Group C, with an impressive five wins in a row securing second place.
The way they have pushed on and been able to maintain a steely composure throughout the campaign is really positive and if they manage to take another big step without their star man it will be a monumental achievement.