FORT WORTH, Texas (REUTERS) - World number two Jordan Spieth was one stroke behind halfway leaders Webb Simpson and Martin Piller after the second round on the Colonial tournament in Fort Worth, Texas on Saturday.

Overnight leader Bryce Molder, among half the field who returned to Colonial Country Club at the crack of dawn to complete the weather-delayed round, took a while to rub the sleep from his eyes.

He recorded two bogeys in three holes to card 69 and join Spieth and two other Americans, Ryan Palmer and Kyle Reifers at seven-under-par 133.

Local man Piller, meanwhile, had to complete 12 holes, and he recovered from a double-bogey at the par-five 11th, picking up three birdies in the final six holes to shoot 66 and join Simpson (67) in the lead at eight-under.

"I was trying to get one more (birdie) coming in, because I think that would be really cool," said Piller, who was thrilled to earn a third-round grouping with fellow Dallas resident Spieth, along with Simpson.

"I know everybody loves Jordan and that's cool. Nobody really knows about me, and that's okay," he said.

Seventy players survived the cut, which fell at one-over 141.

The third round began early afternoon local time.