World number two Rafael Nadal admits he does not know how his previously injured foot will hold up at the Rogers Cup in Montreal this week.
The Spaniard makes his return to the tour this week after being inactive since losing the Wimbledon final to new world number one Novak Djokovic.
Nadal has starting practising again in the last week and ahead of the start of play at the Canada Masters, he said: "I have to see when I put 100 percent power in my foot. We’ll see.
"I’m arriving here with not perfect preparation."
Nadal has a reasonably easy draw in Montreal, especially compared to Djokovic and world number three Roger Federer.
The former world number one could meet compatriot Fernando Verdasco in the third round this week, while seventh seed Tomas Berdych could be waiting in the quarter-finals ahead of a potential semi-final clash with Andy Murray.