Milos Raonic pulled out of the Miami Open on Sunday after suffering a recurrence of a hamstring injury.
The world number five was due to face Jared Donaldson in the third round, but withdrew after being troubled in the warm-up on Grandstand Court.
Raonic was unable to play at Indian Wells last week due to the same injury and now expects to be sidelined for at least a fortnight.
"It's related to the previous injury I sustained almost four weeks ago, if not a little bit more than four weeks ago, in Delray Beach," last year's Wimbledon runner-up said.
"It's the same muscle in the hamstring up high. It got progressively worse after my first round, after practicing yesterday, and it seemed like it was not possible for me to compete today without putting myself at significant risk.
"Right now the perspective is going to change a little bit. Obviously the goal through these tournaments being on hard courts was that I can come back as soon as I feel ready.
"I think that that perspective is going to change to come back when I feel like I'm 100 per cent. That could be in two weeks; that could be a little bit longer. I think the ideology behind when I'm back playing matches and competing, it will be in the sense that that's the best shape my body could be in."
Raonic joins Andy Murray and Novak Djokovic on the sidelines after the top two players in the world missed the Miami Open due to elbow injuries.