Espanyol are furious that Robert Lewandowski could play in Saturday's derby after Barcelona secured a temporary injunction that put his three-match ban on hold.
Poland international Lewandowski was shown two yellow cards in the first half of Barca's last match before the World Cup break – a 2-1 win at Osasuna on November 8.
The Spanish Football Federation (RFEF) issued Lewandowski with an extended three-game punishment due to an alleged gesture made towards referee Jesus Gil Manzano after being dismissed, although the player said it had been aimed at his own coach, Xavi.
The full ban may yet apply, but for now it is on hold after "the dispute settlement court in Madrid issued a precautionary measure against the suspension imposed by the Court of Arbitration for Sport (CAS)" on Friday.
Espanyol are unsurprisingly infuriated such a situation now renders Lewandowski – who has scored 13 goals in 14 LaLiga games this season – eligible to play at Camp Nou on Saturday.
Los Pericos suggested the decision threatens the integrity of the competition because the round of matches has already started, while they are bewildered why such a ruling has been given when Lewandowski's sanction had been supported by three bodies: LaLiga, the appeals committee and CAS.
Espanyol's statement read: "Espanyol finds it unusual that, 24 hours before the match against Barcelona, and after it was rejected by different competent bodies (competition, appeal and CAS), a precautionary measure has been granted to a previously imposed sanction to the Barcelona player, Robert Lewandowski.
"In this sense, as an indirectly involved party, we were only able to have access to the resolution after requesting it from different bodies and not because it was communicated to us, as established by the procedural regulations.
"However, we believe that the requirements are not met to justify the precautionary measure. Specifically, the appearance of good law is particularly indefensible as there are two sanctions of different types, three unfavourable administrative resolutions and an arbitration act with a presumption of veracity that support the sanction.
"Likewise, there is talk of irreparable damage to Barcelona without assessing the irreparable damage to its rivals and the competition without giving the possibility of any recourse.
"The club considers that this last-minute decision completely conditions this matchday, which started yesterday (Thursday), and the team's preparation for this match. RCD Espanyol understands that it is a grievance and an injustice considering the precedents with other clubs.
"Despite this injustice and this unprecedented decision in the competition, our team tomorrow will compete 110 per cent to live up to the trust of our fans."