Former Manchester United striker Dimitar Berbatov fears the performance of some players could suffer in the absence of spectators and a normal atmosphere at stadiums.
A number of football leagues around the globe will resume after the COVID-19 stoppage in the coming weeks, but the matches will be played without fans.
The German Bundesliga season will restart on May 16 after a suspension of more than two months, and championships in South Korea and Faroe Islands are resuming this weekend.
“Playing behind closed doors isn’t going to be the same and everybody knows that,” Berbatov said.
The 39-year-old Bulgarian, his country’s all-time leading goalscorer with 48 goals, also played for Tottenham Hotspur and Fulham in the English top flight.
He also featured for German club Bayer Leverkusen and AS Monaco in France.
“It will be quiet and you will be able to hear all the players talking on the pitch and communicating with their coaches,” Berbatov said.
“The atmosphere won’t be there and it’s going to be different for every team. Some are going to take it (and say) `okay’ and others may suffer from it.
“Sometimes it can affect you performance when you go out there and there are no fans.
“You know it’s a serious game, but in a way you body and mind can tell you it’s like a practice game, which can lead to bad games and performances, which isn’t a good thing.”
Berbatov, Bulgaria’s Footballer of the Year on seven occasions, joined Manchester United from Spurs in 2008 for a then club-record fee of 30 million pounds (37.1 million dollars).
“We all know that sometimes fans can win a game,” Berbatov said.