Five of the nine Masters events, which are a level below the Grand Slams, are 12-day tournaments with 96-player draws. The ATP said in March that two more would go the same way from next year to enhance the experience for fans.

Both Madrid and Rome joined the list last year and Zverev, speaking ahead of the Italian Open, said it was not ideal playing back-to-back tournaments of that scale.

"The two-week Masters 1000 events are great for players ranked between 50 and 100 in the world because they get a chance to play a main draw event," Zverev told reporters. "It's not great for top 10 players. It's as simple as that.

"Yes, you do get told you have a day in between, you don't have to play everyday. At the end of the day that's not resting. Resting is when you're spending time at home, sleeping in your own bed, maybe with your family, your dogs, your kids, right?

"A day between matches, if you're at a different place, that's not resting. If you're going deep in events ... if you're trying to make the semi-finals or finals of every event, you're just away a lot longer and you have to work a lot more."

Both world number two Jannik Sinner and number three Carlos Alcaraz will be absent from Rome due to injuries that have hit their preparations for the French Open, which starts on May 26.

Zverev said reducing the length of the season could help players avoid injury.

"If we have an 11-month season, like we have now ... it's just simply not enough time. It's not enough time to rest your body. It's also not enough time to physically prepare your body," he added.

"Physical preparation isn't how much you practice on court, how much you play. It's how much work you put in the gym, on the track, outside the court, that you can't do during the season."