Monaco says top scorer Radamel Falcao will be out for up to three weeks after sustaining a left thigh muscle injury during a 3-2 home win against Lyon.
The Colombia striker limped off early in the second half of Sunday's game, having earlier scored his 17th league goal of the season and 23rd overall.
Defending champion Monaco, which is in third place and one point behind Marseille, travels to play Angers on Saturday.
In Falcao's absence, and with fellow striker Keita Balde suspended for his sending off against Lyon, Stevan Jovetic is likely to play in attack.
Jovetic set up Rony Lopes' late winner against Lyon, after replacing Falcao.
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