“CAS rejects the suspension request,” the international sports court said in a statement.
Christian Constantin’s assault of former Swiss coach turned TV consultant Rolf Fringer last September initially earned him a one-year suspension, reduced by three months on appeal.
Both Constantin, 61, and Sion lodged an appeal against the sanction, which was accompanied by a fine, reduced from 85,000 euros ($100,000) to 25,700 euros on appeal.
Then last month, they requested “the overturning of the decision taken by the Swiss Football League’s appeals court” in December.
“This request was rejected yesterday,” CAS said in Saturday’s statement.
Instead, the sports court said it had “summoned the parties to a hearing on February 13, 2018.”
Geneva lawyer Olivier Carrard had been appointed as the sole arbitrator in the case, it added.
While rejecting the call to suspend the previous ruling, CAS said Carrard would have maintain the possibility to do so during the hearing later this month.
Video captured at the September 21 match in Lugano, which Sion won 2-1, shows Constantin striking Fringer while he is already on the ground.
Fringer, who managed the national side in the 1990s, told Swiss media that Constantin had in fact struck him several times before the blow that was caught on tape.