Raphinha is reportedly poised to make his first start for Brazil in the early hours of Friday morning against Uruguay in a World Cup qualifier.
The 24-year-old faces a 36-hour turnaround to join Bielsa's side who travel to face the Saints on Saturday afternoon but the Leeds boss says Raphinha could still be in contention to feature in the league game.
Marcelo Bielsa refuses to rule Brazilian Raphinha (left) out of Leeds' game on Saturday
The 24-year-old could make his first start for Brazil in the early hours of Friday morning
'There is no doubt that it's a short turnaround,' Bielsa said. 'The options he has to participate in the game on Saturday depends on whether he plays this final game tonight, how many minutes he plays, how he finishes the game after participating in it and how efficient his rest in the next 36 hours is.
'Considering that a third of those hours he will spend on a flight and if there is any risk that fatigue could cause injuries, then we won't risk it.
'There are so many aspects to consider that I can't offer you any certainty either way.'
Although the government's quarantine rules have been relaxed to allow players to train and play on their return from 'red list' countries while they isolate, some South American Premier League players face tight turnarounds to be able to play in their teams' fixtures this weekend.
Marcelo Bielsa (left) admits it will be a tight turnaround but insists the winger has options
Several Premier League sides have chartered a private jet to ensure that their South American players