SAN DIEGO — The second round wrapped up on Thursday with 3 players sharing the lead at 13-under after the first two rounds.
Adam Schenk, Jon Rahm and Justin Thomas shared the lead after the second round leading into the cut.
The field has now been reduced to the top 70 players and ties at 3-under for the first two days. The final two rounds will be played on the South Course and the winner will receive $1.512 million.
The tournament has been shifted to a Wednesday through Saturday format to avoid a conflict with Sunday's telecasts of the NFL conference championship games. The scheduled Saturday finish is the first on the PGA Tour since the 1996 Waste Management Phoenix Open.
WATCH: Aerial views above Torrey Pines Golf Course for the Farmers Insurance Open PGA tournament
Wednesday, Round 1 recap:
Billy Horschel held a one-shot lead over fellow American Michael Thompson entering Thursday's second round of the $8.4 million Farmers Insurance Open at Torrey Pines Golf Course.
Horschel said when he woke up Wednesday he "didn't know if I was even going to tee it up" because of a neck and shoulder issue that has bothered him since he returned to his home in Florida after playing in the Sony Open in Hawaii that concluded Jan. 16.
"Even when I was hitting balls (on the driving range) I still wasn't sure whether I was going to tee it up," Horschel said. "Made some swings and it felt good on the range and I said I'll give it a shot."
Horschel then equaled his lowest score in his 282 starts on the PGA Tour, firing a bogey-free 9-under 63 on North Course, beginning with back-to- back birdies on the first and second holes. The 35-year-old Horschel also birdied the fifth, seventh, ninth, 11th, 12th, 14th and 17th holes.
"I hit it really good," said Horschel, who is seeking his seventh win on the PGA Tour and first since the World Golf Championships-Dell Technologies Match Play last March. "I mean, I think the longest putt I made was probably on my second hole, I made it from about 25 feet.
"Everything else was inside 10 feet, inside 15 feet. Hit some really good iron shots, which I haven't done well the last couple years. My iron game's really been holding me back, so it was nice to see some of the work we did last week come to fruition this week. Played really solid, didn't put myself in any trouble and shot a really good golf score today."
This is the second time Horschel has led or shared the lead in a PGA Tour event. The other time was in the 2014 Tour Championship which he went on to win. Since 1987, two first-round leaders or co-leaders have gone on to win the Farmers Insurance Open -- George Burns in 1987 and Patrick Reed last year.
Only one first-round leader or co-leader has won in the 12 completed PGA Tour tournaments in the 2021-22 season, Cameron Smith at the Sentry Tournament of Champions.
Thompson's bogey-free 8-under on the North Course was his lowest score in his 31 rounds in the Farmers Insurance Open.
"I'm not one of the longest hitters on tour so I've got to do everything right on a course like this and today I did," said Thompson, who is seeking his third career PGA Tour victory and first since the 2020 3M Open. "I was really hitting my lines. I hit a lot of fairways, which is key out here, and most of my iron shots were right on the money."
American Kevin Tway and German Stephan Jaeger are tied for third at 7- under 65, two shots behind Horschel.
Spaniard Jon Rahm, the world's top-ranked men's golfer, had the day's best score on the South Course, a 6-under 66 with six birdies, two bogeys and an eagle on the par-5 18th. Rahm is among four golfers tied for fifth, three strokes off the lead.
"The conditions were relatively easy," said Rahm, who won the 2021 U.S. Open on Torrey Pines' South Course and his first PGA Tour victory came at the 2017 Farmers Insurance Open. "There's not much wind, but you've still got to play this golf course.
"I hit it great off the tee, put myself in really good positions, and the few times I was off, for the most part I was able to give myself a chance to save the hole so I think that was the key. Nothing was really bad, I feel like everything was feeling good, everything was coming out and feeling the way it should and it showed in the score."
Of the 30 players that shot 67-or-better, only four did so on the South Course: Rahm and Americans Luke List, Peter Malnati and Cameron Tringale. List, Malnati and Tringale are among 22 golfers tied for ninth at 5-under 67, four strokes off the lead.
The 156-player field also includes two of the three other 2021 major tournament winners -- PGA Championship winner Phil Mickelson, who was born and raised in San Diego and now lives in Rancho Santa Fe, and Masters champion Hideki Matsuyama, along with 2021 Olympic gold medalist Xander Schauffele, a San Diego State and Scripps Ranch High School graduate.
Mickelson is tied for 141st, after shooting a 4-over 76 on the South Course, the second consecutive week he has opened with a score of 76 or worse. He shot at 6-over 78 last Thursday at the La Quinta Country Club, en route to missing the cut at The American Express.
Matsuyama is tied for 96th after shooting a par-72 on the South Course.
Schauffele shot a 4-under 68 on the North Course and is five shots off the lead.
The golfers who played the South Course on Wednesday will play the North Course Thursday, while golfers who played the North Course on Wednesday will play the South Course.
The field will be reduced to the top 70 players and ties following conclusion of the second round. The final two rounds will be played on the South Course.
The winner will receive $1.512 million.
The tournament has been shifted to a Wednesday through Saturday format to avoid a conflict with Sunday's telecasts of the NFL conference championship games. The scheduled Saturday finish is the first on the PGA Tour since the 1996 Waste Management Phoenix Open.
Tee times will be pushed back so CBS' telecasts of the final two rounds Friday and Saturday end just before the start of prime time in the Eastern and Central time zones where the bulk of the nation's population lives. Play is expected to end at approximately 4 p.m. Thursday and around 5 p.m. on Friday and Saturday.
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