The 29-year-old came off in the 83rd minute of his side's 1-0 defeat to Lille on Saturday and is now likely to miss a particularly tough run of fixtures for his club after undergoing an MRI scan.
Currently 18th and two points off the bottom of Ligue 1, Valenciennes face top-half sides Nantes, Guingamp, Bordeaux and Monaco before the turn of the year, and come up against Bastia and Marseille, who are also in the top 10, in early January.
Prior to undergoing tests to determine the severity of the injury, coach Ariel Jacobs had been pessimistic about the forward making a return before the end of 2013.
"The way he moved, I doubt," he said.
Le Tallec has made 12 league appearances for Valenciennes this season, scoring just one goal.
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