UEFA rules stipulate that each association can have a maximum of five clubs in the Champions League for the 2016/17 season, meaning if Manchester City win this season's competition and Liverpool win the Europa League, the fourth-place side will have to drop out, provided Manchester City and Liverpool do not finish in the top four.
That means the likes of either Arsenal, West Ham or Manchester United, all in and around the top four places at present, would lose their Champions League reward if they finished fourth.
UEFA rules now state that Europa League winners automatically qualify for Europe's elite competition, as well as Champions League winners.
The previous maximum number an association was permitted in the Champions League was four, a scenario which saw Tottenham drop out of the Champions League for the 2012/13 season despite finishing fourth, thanks to sixth-place Chelsea's Champions League final win over Bayern Munich in May 2012.
Manchester City reached the last eight of the Champions League for the first time this week with a 3-1 aggregate win over Dynamo Kiev, while Liverpool got past Manchester United on Thursday night to reach the Europa League quarter-final.
United are currently four points behind rivals City in the race for the Champions League spots, but they face off in a crucial Super Sunday clash.
West Ham, meanwhile, are two points behind Manchester City with nine games remaining, while the likes of Southampton, Stoke and Chelsea would not rule themselves out of pulling themselves into contention.