Picamoles was forced from the field after just 15 minutes in France’s close shave 23-21 victory over Italy on Saturday.
The French confirmed that Picamoles had pulled hamstring in his right leg and “will miss France’s next games and must rest for several weeks”.
New head coach Guy Noves accepts his squad have plenty of hard work ahead after they produced a late comeback to finally see off Italy.
Heading into the last five minutes at Stade de France, the Italians led only for Jules Plisson’s long-range penalty to deny Jacques Brunel’s side a famous victory, with Italy captain Sergio Parisse also missing a drop-goal attempt in added time.
“Despite a very short training period ahead of the game, we managed to win and with a very refreshed team, so the boys showed a lot of enthusiasm,” Noves said. “However, we did not always play with a clear head and there were no rhythm changes.
“We did not play fast enough. I had the feeling that players aged between 20-29 were actually 35, so we will have to talk about this.
“It is good to take risks, but you have to be intelligent too, that is to find the balance between the will to play and managing the game.”
Despite the manner of what was in the end a somewhat fortuitous victory, there were still some positives for Les Bleus, notably the try-scoring debut of Fiji-born wing Virimi Vakatawa, while Damien Chouly and Hugo Bonneval also went over.
Noves said of Vakatawa, who is a regular in the Sevens code: “He lived up to our expectations, shook his opponents and did not overthink it for his first (France) game. I hope he will continue to improve.”
Medard, Bonneval, Fickou, Danty, Vakatawa, Plisson, Bezy, Ben Arous, Guirado, Slimani, Jedrasiak, Maestri, Lauret, Chouly, Picamoles.
Doussain for Medard (77), Mermoz for Fickou (56), Atonio for Ben Arous (50), Poirot for Slimani (50), Flanquart for Jedrasiak (72).
Odiete, L. Sarto, Campagnaro, Garcia, Bellini, Canna, Gori, Lovotti, Gega, Cittadini, Biagi, Fuser, Minto, Zanni, Parisse.
McLean for Odiete (55), Haimona for Garcia (70), Palazzani for Canna (77), Zanusso for Lovotti (65), Giazzon for Gega (56), Castrogiovanni for Cittadini (65), Bernabo for Biagi (43), van Schalkwyk for Zanni (66).
JP Doyle (RFU).