The North American outdoor hard swing is gathering momentum under its belt as the heat is gaining intensity prior to 2017 US Open. With only two weeks left until the last Grand Slam of the current season starts, the elite ATP herd is having another significant stop in at Cincinnati in Ohio. The second Masters 1000 of the summer swing may lose another high-calibre name as Roger Federer is yet to make his decision about his participation at Western&Southern Open. A runner-up in Montreal at Rogers Cup, the Swiss tennis star has to decide which path he should follow.

Although it may be tempting to sign in and compete this week and possibly capture the world No. 1 spot before US Open, the safest bet should be entirely placed on the fourth Major of the season.

Federer lost to Zverev, slows down the rhythm

Entering Rogers Cup in Montreal, Roger Federer was in possession of some near-to-perfection numbers. His 31-2 win/ loss record suffered some changes as he is now 35-3. The young Alexander Zverev confirmed his great shape pushing up the momentum from City Open into Montreal's field. It's already the second Masters 1000 title for the new ATP sensation and he must be put in the favorites' slot for any upcoming big ATP event. On the other side, the first event on the American hard was not that great for Federer.

He took an advantage of a favorable draw and made it to the final act without being forced to deal with a strong opponent up until yesterday when Zverev emerged on the other end of the court. It's an obvious decrease of the pace as the 36-year-old need to put in some extra power and sharpness if he wants to have a decent shot in New York.

Usually, Cincinnati poses as a safety net for Roger Federer, especially when it comes to a complete warm-up for US Open. A seven-time former champion in Ohio, 19 times Grand Slam champion may skip this year's edition only to bounce back at Flushing Meadows.

Cincinnati already lacks five top 10 players

The last big test prior to US Open will have a rather thin draw in men's singles.

Novak Djokovic and Stan Wawrinka are out for the rest of 2017, Kei Nishikori, Marin Cilic and Andy Murray are also off the table due to some ongoing injuries. It's an open field and it would become even thinner if Federer decides to skip the event. Given the circumstances, Nadal is likely to be the new world No. 1 next Monday, with Federer charging for the US Open. Alexander Zverev could also prolong his momentum. Raonic and Thiem may use this unexpected opportunity to put their both feet in after having a slow start on the hardcourt.