The right-back, who is on loan from Bournemouth, has been ruled out after suffering a thigh issue.
The Mexico international missed Celtic's recent Premiership clashes against Motherwell and Dundee United.
He returned to the Cherries for treatment, and the south coast club has diagnosed a quad strain.
The injury is expected to keep him out until early May.
Before this diagnosis, Celtic manager Martin O'Neill had expressed his uncertainty about how many games the 24-year-old might miss.
He said Araujo's absence hinged on how well he responded to treatment.
It remains to be seen if Bournemouth will allow Araujo to return to Celtic before the season ends.
The full-back is a fan favourite and had teased his absence duration by posting an egg timer image on social media last week.
Araujo's loan move to Celtic was intended as cover for Canadian international defender Alistair Johnston, who is out with a long-term hamstring issue.
However, Johnston's return could be on the horizon.
Hopeful of a return in time for the top six split towards the end of April, Johnston says he hopes to be fit for the final five league games.
Johnston said: "In an ideal world I would like to be back in time for the split,"
"And I think that’s a realistic target, but at the same time none of us are writing anything in stone.
"But if I need an extra week then I will take an extra week. I don’t have an exact date. We will all take it week by week."
Celtic has been blighted with injuries throughout the season.
They have been without central defender Cameron Carter-Vickers and Portuguese winger Jota.