Du Plessis out for month with hamstring pull
Du Plessis out for month with hamstring pullSHARE
The 34-year-old Springbok international was injured during Montpellier's 3-16 defeat at Lyon on Saturday, being forced off inside the opening half hour.
Du Plessis's injury is another headache for Montpellier, who already have Georgian prop Davit Kubriashvili out until April with a calf problem.
Australian international fullback Jesse Mogg will be rested for a week after taking a knock to the head against Lyon that saw him forced off the field for a head trauma assessment.
However, there is better news for Montpellier as Fiji wing Nemani Nadolo, who was knocked out against Castres at the end of January, is set to make his return for the trip to Clermont.
Montpellier sit fourth in the Top 14 with Clermont second.