Arsenal striker Eduardo has been banned for two Champions League games by UEFA for diving to win a penalty against Celtic last week. Eduardo will miss Arsenal's Champions League group matches away at Standard Liege on September 16 and the home match with Olympiacos on September 29.
The Gunners have three days to lodge an appeal.
UEFA said in a statement: "The UEFA control and disciplinary body examined the case of the Arsenal player Eduardo 'for deceiving the referee' during the UEFA Champions League play-off second leg match on August 26 against Celtic, and has suspended the player for two UEFA club competition matches."
Arsenal released a statement on their website condemning the "arbitrary" nature of UEFA's decision.
It read: "The club is disappointed with UEFA's decision to suspend Eduardo for two Champions League matches starting with Standard Liege on September 16.
"We have been informed that we will receive a 'reasoned decision' from UEFA by Thursday of this week.
"Once we receive UEFA's rationale, we will make a decision on the next steps.
"We have been deeply frustrated by the perfunctory and apparently arbitrary process that UEFA has followed in this instance.
"We believe it is imperative that UEFA's explanation for its decision provides clear and comprehensive standards that will be consistently enforced.
"It is also critical that UEFA provides specific details of the processes it plans to adopt in reviewing all games under its jurisdiction."