Pep Guardiola expects post-Brexit employment regulations to impact on English football clubs.
The United Kingdom's departure from the European Union could mean non-British players having to apply for work permits to play in the Premier League.
Under the freedom of movement principle, players from EU countries are not presently subject to immigration regulations.
It is possible that from 2019, when the UK is scheduled to leave the EU, that players may have to satisfy authorities they are regular internationals for their countries to earn work permits. This is currently the case for players from outside the EU.
Such a scenario could drastically affect Premier League clubs, who have come to rely heavily on foreign - and particularly EU - players in recent years.
It has been suggested separate arrangements could be made for highly-skilled workers, among which footballers could be bracketed but all of this is subject to negotiation over the next two years and nothing is clear.
Manchester City manager Pep Guardiola is unsure whether such a scenario would be workable.
Guardiola, himself a Spanish national, said: "What happens in two years - it's a new situation and you have to adapt.
"The work and the rules have to be the same for everybody.
"Why would football be exceptional to lawyers or architects who are not able to work? But football players yes? Why?"