The game's governing body hit Suarez with a four-month ban from all football-related activity after he bit Giorgio Chiellini during Uruguay's World Cup clash with Italy on June 24.
A subsequent appeal against the sanction - which also includes a nine-match international suspension - was rejected by FIFA, with Suarez's legal team now taking his case to the Court of Arbitration for Sport (CAS).
That means the 27-year-old, who has been punished for biting twice previously, will not be able to play for new club Barcelona - who he joined from Liverpool in a deal worth a reported £75million earlier this month - until late October.
Due to the fact Suarez's ban encompasses all football-related activity, he has also yet to be publicly presented as a Barca player and cannot train with his new team-mates. And his former club colleague Aspas, who spent the 2013-14 season with Suarez at Anfield, believes the punishment is too harsh.
"They are treating Luis like a murderer and not like a footballer," the forward, who signed for Sevilla on a season-long loan deal last week, told Spanish radio station Cadena Cope.
"There are murderers who pay less. To not let him be presented, to train or to enter the stadium is too much."