The Sevilla stopper has been banned for four matches after video evidence showed that he deliberately stamped on Salgado's knee during the Andalucians' 3-0 defeat at Santiago Bernabeu on January 2.
"I want to apologise to Michel publicly and ask him to pardon me," said Alfaro.
"The ban is hard, but I have been given it and I have to accept that. I committed an error and now I must pay for that.
"I know what I did was wrong, but if my club appeal on my behalf then so be it.
"I have the utmost respect for Michel because he is the only one who has the right to criticise me and he is the only one who hasn't.
"I would like to thank him for his professional behaviour. What I did happened in the heat of a game and was between two professionals and I am sorry."
Alfaro could still play in this Saturday's Andalucian derby against Malaga if Sevilla appeal against the ban and the Spanish Football Association (RFEF) agree to suspend it.
