The former top-ranked player injured a muscle below his ribs on his left side. He said it happened after he arrived Monday.
"Perhaps I started hitting balls a little cold after the long trip, or didn't warm up properly," Singh said. "Coming off the flight I was fine and I was excited about playing."
Singh, who tied for third in last year's championship, said he still hoped to play when he went to the range Thursday morning.
"It was OK until I hit a 3-wood and it kind of started catching me again," he said. "It is a very sharp pain which was unbearable at times. I don't get injured that often and this is a weird one. It is not my ribs, it is not my back. It is the oblique muscle in my ribs. I think there might be a little tear in there as well."
Singh said he would return home to Florida and would try to play at the Memorial next week.