The Premier League is considering whether to "reward" clubs whose coronavirus vaccination rates are high.
There have been concerns about the rate of vaccination among players with some contracting Covid-19.
The Premier League said: "We are considering if and how best we can 'reward' those squads/players who are most Covid-compliant."
Newcastle goalkeeper Karl Darlow was hospitalised in July and Chelsea's N'Golo Kante tested positive this week.
"Only seven clubs' squads are more than 50% fully vaccinated, so we have a way to go," the Premier League continued in an email sent to the top flight clubs last week.