Phil Mickelson scrambles to a 68 at PGA Tour’s CareerBuilder Challenge

Phil Mickelson shot a scrambling four-under-par 68 on Thursday in the CareerBuilder Challenge, leaving him four strokes back in his return from two sports hernia surgeries.

“I struck it horrible, but I scored out of my mind,” Mickelson said. “So, I’m very happy with it. My first round of golf was Saturday and I’ve been able to work out just the last two weeks.”

Lefty hooked his opening drive into the trees in the morning rain and cold at La Quinta Country Club, a drive so bad that he hit a provisional even though he thought the first one was in play. It was, and he hammered a shot under the trees to just off the front of the green and saved par.

“I figured the ball was OK. I just played a provisional, mainly to get another swing,” Mickelson said. “That next hole, the second hole’s an extremely difficult drive and I wanted to just get another swing.”

Tour rookie Dominic Bozzelli shot a 64 on the Stadium Course at PGA West — the most difficult of the three courses — to top the leaderboard. He holed out from 115 yards for eagle on the par-four 14th.

“Been working hard back home, doing all right things on and off the course, and it’s nice to come out and have that hard work pay off,” Bozzelli said.

Jhonattan Vegas, the 2011 champion, was a stroke back at 65 along with Harold Varner III, Hudson Swafford and Patton Kizzire. Vegas and Kizzire played PGA West’s Jack Nicklaus Tournament Course, and Varner and Swafford opened at La Quinta.

Rain fell off and on in the morning and more was expected Friday, with the PGA Tour moving the tee times up an hour.

“Ain’t nobody never comfortable when you’re having to play golf when it’s raining and a little cool like it was,” Boo Weekley said after a 66 on the Stadium Course.

Play started with the temperature in lows 50s and it barely climbed into the 60s in the afternoon. The forecast high Friday was 61.

“The ball didn’t go as far, but you don’t have to hit it that far out here,” Varner said.

The 46-year-old Mickelson had surgery Oct. 19 — three days after tying for eighth in the season-opening Safeway Open — and again Dec. 12.

“I feel fine,” Mickelson said. “I’ve been able to work out the last two weeks. And again, you start out real slow, but you get back to it, you get it back pretty quick.”

His caddie, Jim “Bones” Mackay also made a comeback after having both knees replaced.

Mickelson won the 2002 and 2004 events and tied for third last year. The first-year tournament ambassador won the last of his 42 PGA Tour titles in the 2013 British Open.

“There’s no better place to learn and to get better than to come out here on these great golf courses and put it to the test,” Mickelson said. “You can get away with some mistakes, and I was able to salvage a few pars with up-and-downs, so it doesn’t beat you up too bad. It’s a perfect place to start the year.”

Lefty hit a wedge to within two feet for birdie on the par-four fourth and also birdied the par-five sixth and par-four eighth. On the par-four ninth, he made a 45-foot birdie putt after driving left onto the adjacent first hole.

Mickelson had his best par save on the par-four 16th after losing another drive to the left. He hit under the trees into the front left bunker, blasted short into the fringe and holed an 18-foot chip. He bogeyed the par-four 17th after driving into the left bunker, and made an eight-foot birdie putt on the par-four 18th.

Bill Haas, the 2010 and 2015 winner, played alongside Mickelson and matched him at 68.

Patrick Reed, the top-ranked player in the field at No. 9, had a 69 at La Quinta. He won in 2014, shooting 63-63-63-71 to break the PGA Tour record for relation to par for the first 54 holes at 27 under and become the first player in tour history to open with three rounds of 63 or better.

Defending champion Jason Dufner shot a 70 at La Quinta.