Carvalho got a straight red card for a two-footed challenge on Aston Villa's Gabriel Agbonlahor on Boxing Day, one week after Liverpool striker Crouch was sent off for a lunge at Mikel John Obi.
"When you go with intention to hurt players, I don't like it," he said. "For me it is clear that this is not the same situation, and we apologised anyway. Peter Crouch was angry, he said Mikel did something to him. He (Crouch) did not even apologise. He said many other things that were not clever."
He added: "People said he is racist which I don't believe - but there is a difference because Carvalho immediately - even though he did it with no intention - apologised. Why didn't Peter apologise?"
Grant has also instructed his players not to tackle with two feet after the current trend of punishing the challenge with a straight red card.
He also feels there could be clarification on the rules.
"I am a manager since September but I didn't hear it before," he said. "The communication needs to be better, maybe from our side also."
Grant has senior players such as John Terry, Frank Lampard, Claude Makelele and Didier Drogba on the sidelines injured at the moment and is looking at targets for the January transfer window.
"We want players of the right quality," he said.
"It would be an advantage if they can play in Europe, although the Champions League is in February and I expect the injured players to come back and the African players."