Lyle in the hunt in Phoenix

Ryan Palmer fired a seven-under 64 to take the outright lead in the suspended first round of the Phoenix Open.

Thursday's play was delayed by an hour due to frost, before darkness prevented several players from finishing their opening rounds at TPC Scottsdale.

American Palmer, a three-time winner on the PGA Tour, carded eight birdies and one bogey to lead compatriot Webb Simpson by one stroke.

Simpson, who started on the 10th hole on the Stadium Course, led for most of the day before bogeying the sixth and closing out his round with three consecutive pars.

"I knew I was going to be here in the morning for the second round, so I wasn't worried about it if we had to come back and restart," Palmer said.

"So, I didn't think about it and I just kept hitting shots and sticking to my game plan."

Eight players are tied for third place on five under, with Australian Jarrod Lyle the only non-American among that group.

Lyle was a late addition to the Phoenix Open field after Nick Watney pulled out through illness earlier in the week.

PGA Championship runner-up Jason Dufner is among those tied with Lyle, as is US Presidents Cup representative Bubba Watson.

Another high-profile player in contention is Phil Mickelson, who bounced back from a missed cut in last week's Farmers Insurance Open with a three-under 68.