The global footballers' union (FIFPro) on Friday said it was worried about the crowded schedule players face as the game resumes and urged a five to six-week rest after this coronavirus-interrupted season ends.
"Since the restart we are seeing a first spike in injuries because of insufficient preparation time and congested match schedules," FIFPro wrote in a statement.
"The impact of COVID-19 means the match schedule will be even more intense over the next two years. The response must be better and innovative safeguards for player health and not the erosion of the few existing frameworks," the statement said.
While the German Bundesliga, which resumed on May 16, is set to finish June 27, the Spanish, Italian and English top flights are sprinting to finish by August 3.
That will be followed by the completion of the 2019-2020 Champions League and the Europa League in August and, almost simultaneously, the start of the preliminary rounds for the 2020-21 European competitions.
The 2020-21 season is followed by the postponed Euros and Olympics.
FIFPro, which is based in the Netherlands, suggests a rest period of "five to six weeks" before resuming training for the start of the next season, adding that "the minimum contractually-agreed holiday periods need to be respected... in most countries this is at least three weeks".
"It is not acceptable that altering competition calendars leads to pressure to breach these rights."
The union also urges "a mandatory mid-season break of between 10 and 14 days".
It welcomes the five-substitute rule and said it "should be extended".
UEFA has already said it will revert to three replacements next season.
Doing his duty: FIFPro cited Tottenham's Son Heung-min, who spent the coronavirus break doing military service in South Korea while recovering from injury, as as an example of an overworked player after he appeared in 78 games in 12 months