Pep Guardiola admits he is confused by some of the coronavirus regulations in the game.
The Manchester City manager says he does not know why some games have been postponed due to a high number of positive tests within squads while others have not.
Four Premier League matches have so far been postponed, including City's trip to Everton last month, but a different approach appears to have been taken in the FA Cup over the weekend.
Both Aston Villa and Derby fielded sides made up of youth players for their third-round ties after their entire first-team squads were told to isolate.
Guardiola is also not sure if it is realistic to expect players not to celebrate goals. The Premier League last week called on players to tone down their celebrations in a set of reinforced coronavirus protocols that also emphasised the need to avoid handshakes and shirt-swapping.
In the meantime City's own problems with Covid-19 have continued as Sergio Aguero was forced to miss Sunday's 3-0 victory over Birmingham in the FA Cup third round.
The Argentinian has been told to self-isolate after it was discovered he is a close contact of someone who has tested positive for the virus. City have already been without eight other players following positive tests at various stages since Christmas Day.
Guardiola did not express a particular opinion on these matters when asked, but said he did not understand all the rules.
The Catalan said: "I read them, the new protocols. We are going to follow them. But when one guy scores a goal, I don't know if they can be controlled and not celebrate it.
"All of us (involved on match days) are tested negative, every two days. I don't know what is going to happen – but one guy scores a goal, the joy to celebrate it, I don't know if he is going to think, 'I cannot hug my mate for two, three seconds'.
"There are teams with four or five cases and played 10 players from the under-23s in the FA Cup. We are four or five, the same situation, and we are here.
"One guy is isolated and the group has to continue. So, I don't know. We follow what the people say at the club, the Premier League. We follow the rules. That is what it is.
"Sergio was in contact with one person and must be isolated – that is good – but we were in touch with Sergio as well, and we played.
"Aston Villa had 10 players isolated plus the manager. So, I don't know."
What was clear on Sunday, however, was that City's appetite for cup success shows no sign of being sated.
Great brace from this man and top performance from the lads! 💙 pic.twitter.com/ypHRu7iYCe — Phil Foden (@PhilFoden) January 10, 2021
Fresh from reaching their fourth successive Carabao Cup final in midweek, the 2019 FA Cup winners eased past Birmingham to reach the fourth round.
Their Championship opponents were no match for Guardiola's fluid side, who effectively wrapped up victory in the first 33 minutes with a Bernardo Silva double and a Phil Foden strike.
Second-choice goalkeeper Zack Steffen, who made his debut in the competition in what was his third successive appearance due to Ederson's recent positive test, thought it was an outstanding display.
The American said: "We want to lift as many trophies as we can, we want to win as many games as we can and play the best football we can.
"It was a good effort, a professional performance by the guys. We got the job done and now go on to the next one.
"I love playing, it's been great to get out there for a couple of games. I've had guys in front of me that have done a really good job in the last three games and it's been a pleasure."
