Constantin says Sion has no legal obligation to travel to its away games, including a July 31 visit to Neuchatel Xamax, because the case is so serious.
FIFA banned Sion from registering new players in 2011 after it induced goalkeeper Essam el-Hadary to break his contract with Egyptian club Al-Ahly in 2008.
Sion claims it served the punishment cumulatively over several transfer windows.
The Swiss league backed FIFA last Friday, the day before Sion’s opening match at home to Zurich.
Sion won 1-0 despite being without six new signings, including former Barcelona midfielder Gabri Garcia.