Pádraig Harrington's injury woes have forced him to play a game that's alien to his instincts. But he had to admit hitting the ball straight and short was just what the doctor ordered after he fired a four-under-par 67 to lie just three shots off the lead in the fog-delayed Genesis Open in Los Angeles.

As Graeme McDowell shot a solid 69 for a share of 30th with Jordan Spieth (16 holes), Shane Lowry was left facing a 13 footer for birdie on the 17th to get back to two over when darkness fell.

Early starter Harrington was long gone by then and tied for seventh place after a round that must have felt like an out of body experience.

Normally a player who likes to attack, even if that means playing from the rough, the loss of distance he has suffered due to a trapped nerve at the base of the neck forced him to steer the ball around the classic Pacific Palisades venue, hitting 13 of 14 fairways. 

That's unprecedented driving accuracy for Harrington, who holed a 27 footer for birdie at the seventh and a six-footer for another at the driveable 10th before recovering from his solitary bogey at the tough 12th with three successive birdies to finish.

"It was nice," he said after his round. "I have been putting well, and I didn't play any practice rounds this week —I've been injured— so I didn't quite know what to expect. 

"I hit the ball pretty straight all day —short and straight— and I holed some putts. It's not my usual way to playing golf, but I will certainly take it."

Harrington still missed six greens but he got it up and down for par everywhere bar the 12th, where he missed the green long left and left himself a tough par putt.

"As I said, I  have been injured, and I have just been struggling to get my head around the injury," Harrington said after finishing with birdies from eight feet, 21 feet and 15 feet on the last three greens. 

"I think this is a nice golf course in that you don't have to hit it [far] off the tee very often. You are better off hitting it straight and I can manage my way around here and not feel too bad about not being up to full power."

He went on: "It is a comfortable golf course to play. Everybody enjoys playing it and that makes it a little easier for me."

As for the injury that has hampered him in his first three starts of the year and caused him to miss the cut in San Diego, Phoenix and Pebble Beach, he said: "I seem to have a trapped nerve in the C7. 

"I have got numbness in my hand —pins and needles— and I have atrophy in my right triceps and all sort of things going on. 

"Basically, I have no pain. But I have a power loss on the golf course and I am struggling to hit it."

American Sam Saunders, the grandson of Arnold Palmer, shot a seven under par 64 in his first competitive round at Riviera to take a two-stroke clubhouse lead in the clubhouse over Dustin Johnson, J.T. Poston, Daniel Summerhays and Brett Stegmaier.

His round, his lowest on the PGA Tour, came 50 years after his grandfather successfully defended the title in L.A.

McDowell made three birdies and one bogey for his two-under 69, scrambling well. 

His 12 footer for par at the second, for example, was just as important as the 22 footer for birdie at the seventh in his first start of the 2017 PGA Tour season.

By comparison, Lowry was not having a great day from tee to green.

He hit just five of his first 13 fairways and as a result, he found just half the greens.

He birdied the fifth from 12 feet, but bogeyed the second, eighth, 12th and 16th and must return early on Friday to tackle a 13 footer for birdie at the par-five 17th.

With bad weather forecast for day two, Harrington may not even get to play, giving him more time to get treatment on his neck. 

Spieth was two-under after 16 holes when play was suspended due to darkness with Hideki Matsuyama on one-under and world No 1 Jason Day on level par.