Robin van Persie in a Chelsea shirt would have banned for elbow - Jose Mourinho
Jose Mourinho believes had a Chelsea player used his elbow in the same way Robin van Persie did at West Ham last Sunday he would have been banned.
Striker Costa was banned for three matches and serves the final game of his suspension when the Premier League leaders play Everton on Wednesday night.
Mourinho's mood has lightened since opting out of media duties surrounding the draw with Manchester City on January 31 and that he was happy in last Friday's return in front of the cameras.
But the Blues boss suggested he still thinks the Football Association's disciplinary department is not being consistent.
"I was in a good mood the other day," Mourinho said.
"I needed a little bit more time to forget why my player (Costa) was suspended.
"I need a little bit more time to understand why some people are punished, others aren't. I need a little bit of time to process that.
"The same people (the FA) that suspended my player didn't want to suspend a player this weekend. This weekend he could."
When asked which player he was referring to, Mourinho gestured with an elbow in a clear reference to Van Persie's challenge on James Tomkins.
"I know that if it was one of mine, I know," Mourinho added.
"Last season happened the same thing, when Ramires was suspended.
"It was exactly the same thing. And one week later a Manchester City player kicked a player on the floor at Norwich and nothing happened."
That was a reference to Yaya Toure's challenge on Ricky van Wolswinkel, which went unpunished.
Mourinho refused to comment on the fact Leicester boss Nigel Pearson avoided sanction for appearing to grab Crystal Palace's James McArthur by the throat.
"I have only thoughts about myself," Mourinho said.
Asked if he would have been charged had he done what Pearson did, Mourinho said: "No comments. You know."
Midfielder John Obi Mikel (knee) is the only definite absentee for Wednesday's match, but Cesc Fabregas (hamstring) is fit again.
The Everton contest sees the return of Romelu Lukaku to Stamford Bridge after the Belgium forward struggled to break through into Mourinho's plans and was allowed to leave the club.
The Portuguese manager said: "He proves every weekend that he's a good player. Nobody has doubts at Chelsea that he's a good player.
"We know Romelu is a good player. (Andre) Schurrle is a good player, (Kevin) de Bruyne is a good player, (Juan) Mata is a good player.
"They are good. We don't sell garbage. We sell top players.
"We sell top players, we get top fees. (Without) top fees we don't sell them, we keep them.
"That's football, that's life, that's market. The player wishes sometimes to be in clubs where they become clearly the first option. That's football, that's life.
"If he's happy, that's good. He wanted to play all the time."