Kim Clijsters defends her new world number one ranking in Toronto, a tournament that's once again beset by injury and withdrawals. No fewer than six of the world's top women have dropped out hurt. More than ever, the grind of the WTA tour appears to be taking its toll, writes Alejandra Sanchez.
The WTA season includes total of 59 tournaments and players are expected to play between 15 and 17 of them a year.
The pressure to take part is hard to resist.
Not only do the players have to maintain their place in the rankings, but they also want to avoid getting rusty.
But the line is thin between being battle-ready and battle-weary.
Late scratches abounded in both San Diego and Los Angeles, including former world number one Venus Williams, who's also passing on Toronto.
For one of those beset by injury in San Diego - three times Grand Slam champion and world number one Jennifer Capriati - the explanation is simple.
"It's a long season and, with the grind of the tour, there's not much time to take a break, let alone recover".
But the length of the season isn't the only cause of injury. Ever since the Williams sisters hit the tennis scene, strength and speed have become vital ingredients to winning.
No soft touch herself, Capriati believes the power game is taking its toll:
"The game is so much more powerful now and maybe some of the girls are over-training trying to get stronger."
Some are savvier than others when it comes to managing their time.
The only top player to have played the full schedule without being injured this season is Roland Garros champion Justine Henin Hardenne. That boils down to a sound management of her schedule.
Before the start of the U.S. Open, Henin will have played only two WTA Tour events: San Diego and Toronto where she's the second seed. During the clay season, Henin played Charleston and Berlin - which she both won - before heading for her first grand slam crown.
The harder hitting Serena Williams herself picks and chooses her tournaments. But that doesn't make her invulnerable to injuries. She won't defend her U.S. Open crown due to knee surgery.
With less than two weeks left before Flushing Meadows, and a total of 9 withdrawals in San Diego, 12 in Los Angeles and 6 in Toronto should send a wake up call to the WTA.
Tour organisers should revise the calendar year and allow players to play fewer tournaments in order to allow them to recover properly for the big events.