Paris Saint-Germain president Nasser Al-Khelaifi told French radio on Thursday that Ibrahimovic is likely to miss "at least four weeks", after the striker collapsed during a Chelsea clash on Wednesday night.
The Swede came off midway through the second half of PSG's 3-1 win in the first leg of their Champions League quarter-final clutching the back of his right thigh and was due to undergo tests on Thursday.
"He is having an MRI scan at the moment and we're awaiting the results," Al-Khelaifi told RMC. "But I think he will be out for at least four weeks."
If Al-Khelaifi's prediction proves to be true, Ibrahimovic will certainly be ruled out of second leg against Chelsea and would also probably miss an eventual semi-final, as well as the French League Cup final against Lyon on .
In his absence, Brazilian winger Lucas would likely come into Laurent Blanc's starting line-up.
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"To play is impossible. I think Zlatan is very important for the team but Lucas is ready," Al-Khelaifi added.
Ibrahimovic has scored a club record-breaking 40 goals in all competitions this season, including 10 in the Champions League.