It follows the Royal Spanish Football Federation stating that there are no non-EU restrictions as the clash is deemed to be "not professional".
Usually in La Liga and Copa del Rey fixtures, only three non-EU players are allowed in a squad.
The Super Cup each year launches the elite Spanish season, pitting the La Liga champions against the Copa del Rey winners. However, because Barca won a domestic double in 2017-18, Sevilla qualify as the Copa runners-up.
For the first time, the Supercopa is being played as a single match this year, as opposed to the usual two-legged format.
The encounter is to be held in Tangier, Morocco.
A Sevilla club statement read: "Sevilla FC is surprised by the RFEF statement only 24 hours before the Super Cup.
"It has stated that as many non-EU players as desired can be registered. In their last notice for the 2018-19 season, only three were due to be permitted, without exception.
"The club's legal department is studying the matter and should FC Barcelona submit a team with more than three non-EU players, it would present possible grounds for withdrawal on account of an improper line-up."
Arturo Vidal, Malcom and Arthur are set to take Barca's three slots. But the club managed by Ernesto Valverde have taken four non-EU players to North Africa, including defender Marlon.
Brazilian Philippe Coutinho is reported to have gained a Portuguese passport this week through his wife. Uruguayan Luis Suarez and Argentine Lionel Messi meanwhile already have EU citizenship due to living in the continent for the required time.