Valenciennes may be without top scorer
The former Liverpool forward has been experiencing pain from an Achilles tendon injury and will at some point be forced to miss a game to rest it.
"Missing a match and resting completely for eight days could cure the inflammation," Sanchez told L'Equipe.
"Our plan is not to do it for Sochaux, but we may have to."
Valenciennes' next game after the Sochaux clash is away to Bastia the following weekend.
Defender Bacary Sagna is convinced Arsenal can win the Premier League again next season - and would have already quit if not.