Roger Federer may skip the Montreal Masters tournament if his sore back doesn't heal. After Daniel Brands upset Federer in the first round of the Swiss Open, the 17-time Grand Slam champion said he has been dealing with back spasms for a few weeks.

"I've had serious problems with the back; I had to get some anti-inflammatories last week in Hamburg due to the pain," he told reporters. "I will have to do a lot of exercises and see how it all feels. My main priority now is to fix my back. I would love to be able to train at 100 percent. I'll have to see if the rehab is enough to let me play in Montreal. If it is, I'll go; if not, then it gives me another week."

Federer, who was also upset by Federico DelBonis in the Hamburg semifinals, said he couldn’t tell whether his switch to a larger racquet is doing him any good.

"A change like this is very important but I honestly can't tell right now due to my low level. It's hard to analyze anything,” he said. "I still don't have even enough information to try and explain. I have no clue where I am right now with the racquet change."