"He has damaged ankle ligaments. My experience in football tells me he will have it for at least two months, but I'm not a doctor so I'm not going to make a prognosis," Michel said ahead of Wednesday's League Cup clash at Toulouse.
Ocampos, 21, suffered the injury during the first half of Sunday's 0-0 draw against Guingamp but has yet to undergo an MRI scan because his ankle is still too swollen, the club added.