It is "unethical" for Premier League players to leak team news to people playing fantasy football, says Manchester City boss Pep Guardiola.
Villa manager Dean Smith said he would look into how the news emerged.
"I know players play these games but I don't know what it is," said Guardiola.
"Sometimes there's a selection and players are friends with other teams and they talk.
"Sometimes it happens, it's unethical and unprofessional but it can happen."
England midfielder Grealish was ruled out of Villa's 2-1 defeat by Leicester on Sunday with a leg injury, ending a run of 48 consecutive Premier League starts.