Pep Guardiola has called upon referees to provide greater protection for players after Leroy Sane was injured during Manchester City's 2-0 FA Cup win away to Cardiff on Sunday.
First-half goals from Kevin De Bruyne and Raheem Sterling ensured Premier League leaders City stayed on a course for the 'quadruple' as they reached the last 16 of the FA Cup.
But some of the shine of this latest victory was removed when Sane failed to take the field for the second half after a bad tackle by Joe Bennett left the Germany winger with an ankle injury.
Cardiff defender Bennett was sent off in the closing seconds for yet another poor tackle on City substitute Brahim Diaz.
"He (Sane) will be out for a while -- minimum two weeks, three weeks, one month, we will see tomorrow exactly," said City manager Guardiola.
"I said many times the only thing they (referees) have to do is protect the players.
"I can accept our disallowed goal, I don't know why but I accept. But please protect the players.
"Not the Man City players, all players. The only thing they can do is that -- to protect the players -- because it would not happen again.
"It happened once with Leroy, then it happened with Brahim again at the end.
"So for the football in general, and for the players who are the artists, they must do that. That's why we are all here."
Guardiola saw his fears echoed by the German football federation for whom Sane will play a key role in the World Cup in Russia later this year.
"Hey, @CardiffCityFC. Just letting you know, we have a really important tournament in the summer. Please don't hurt our players. Thanks, #inSane," tweeted @DFB_Team_EN.
City are 12 points clear at the top of the Premier League and face Arsenal in the League Cup final next month, when they also resume their Champions League campaign.