World number three Alexander Zverev said cutting Masters tournaments back to one week would help players maintain their fitness instead of having to manage their workload and be selective about which events they compete in.
Carlos Alcaraz missed out due to a wrist injury that has kept him out since April.
The withdrawals once again left the tournament without three of the sport's top names after the trio also missed last year's edition.
French Open champion Zverev, who lost his opening match in Montreal, told reporters: "I think that's what two-week events do.
"Unfortunately, especially if there's a Grand Slam coming after that. If you play everything and you're a top player, you spend seven weeks here in North America.
"That is quite a long time and I think that's why a lot of top players choose not to play Canada for multiple years now. That's unfortunately the sad reality of it.
"It's quite simple. Make us be here for two weeks, not seven. For the Masters, it's two weeks for both of them. I think that's an easy fix regarding top players playing," added the German, speaking ahead of the Cincinnati Open.
Since 2025, seven of the nine ATP Masters 1000 events on the calendar have each been held across 12 days, with only the Monte-Carlo and Paris Masters still played over a single week.
Players have criticised the extended events, but the ATP has said they choose their own schedules and that it is working to create incentives for an appropriate number of matches to be played during the season.
