Manchester City have halved Carlos Tevez's fine over his alleged refusal to warm up during a match last month.
The striker has now been fined two weeks wages instead of four for the incident against Bayern Munich.
The PFA had earlier backed Tevez over the punishment and said that they would not give their necessary approval for the fine to be sanctioned.
Now, City have suggested that the PFA have gone back on a previous agreement.
"Manchester City is disappointed by the apparent PFA conflict of interest evident in this process," the club said in a statement.
"Carlos Tevez has been personally represented throughout by the PFA chief executive [Gordon Taylor], on whose considerations the club has been informed that the PFA has made its decision.
"Manchester City has been in constant dialogue with the PFA since September 28. Today's PFA decision is a departure from the club's understanding of that dialogue.
"Without recourse to the PFA decision available, the maximum two-week fine provided for in standard player contracts will now be applied in relation to the misconduct of Carlos Tevez."
The Argentine was also given a two-week suspension which he has already served.