Liverpool manager Brendan Rodgers claims the severity of Luis Suarez's 10-match ban has left them "bitterly disappointed".
The Uruguay striker was handed a lengthy suspension for biting Chelsea's Branislav Ivanovic.
Liverpool have until midday on Friday to appeal and will make their decision after receipt of the disciplinary panel's report, which has to arrive with the club before 6pm today.
"It is the severity of the ban that has hurt most," said the Red boss.
"That is something we are bitterly disappointed with - not so much the ban because everyone has seen it and Luis was very open and honest to know it was wrong.
"I felt it could have been 12 games but with a six-game ban and six games suspended, looking at his future behaviour.
"I don't think anyone would have disagreed with that."
Although the Football Association have since changed their disciplinary system Rodgers referred to two incidents seven years ago which escaped with greater leniency.
England striker Jermain Defoe received no punishment for biting West Ham's Javier Mascherano in 2006 as he was booked at the time while Chester's Sean Hessey was banned for five matches for a bite on Stockport's Liam Dickinson.
"There have been two incidents of this type of scenario. One player (Defoe) received no ban and continued to be chosen by the FA as part of the England squad," he added.
"The second player received a five-game ban - so as you can imagine when Luis Suarez receives a 10-game ban it is very difficult to understand and even more so for Luis.
"This is a guy who has been genuinely trying to change his behaviour and curb his natural instincts: from a young boy his mentality has all been about winning.
"This year he has done a brilliant job, I've seen that first hand and that is why I've always been at the forefront of defending him. And when he hasn't I have spoken and he's understood that.
"But for him to receive that (10-match ban), when the comparisons of the similar incidents is somewhat different, then that is what is hard to take."