CareerBuilder Challenge 2016: Thursday Leaderboard Scores and Highlights

The PGA Tour's annual West Coast trip to California for the 2016 CareerBuilder Challenge provided Jerry Kelly, Jeff Overton, Jason Dufner and Anirban Lahiri with an opportunity to show their skills, as they finished Round 1 in a four-way tie for the lead at eight under par.

Overton and Lahiri were in the clubhouse early Thursday, waiting to see if Kelly would overtake them. Dufner emerged from the shadows late, knocking in a birdie on his final hole to grab a share of the lead.

The quartet is fighting a closely bunched group that includes Colt Knost and Jamie Lovemark, who are one shot back, and 11 more players who are six under par.

Here's the full leaderboard following Thursday's opening round at the PGA West TPC Stadium Course:

Moving down the leaderboard, Phil Mickelson made his 2016 PGA Tour debut Thursday. Lefty has work to do Friday but played well with a 68. He lost steam down the stretch, with bogeys on Nos. 14 and 17 that knocked him down a couple of pegs.

Yet it was encouraging to see Mickelson back in his element after he struggled often last season. He looked to be in good form after hitting shots like this one on No. 8, per the PGA Tour:

According to ESPN.com's Jason Sobel, Mickelson did something Thursday that he hadn't pulled off since 2011:

The key will be carrying this performance into the weekend. First rounds last year were his best, with an average score of 70.63, but the numbers increased over the next two rounds, peaking at 71.13 (third round) before settling down in the final round (71.00).

A new year gives Mickelson a clean slate to prove that 2015 was more of a fluke than an indication his skills are rapidly declining at the age of 45. He's off to a positive start with room for growth. 

Defending CareerBuilder Challenge champion Bill Haas also made a strong first impression, finishing six under par and starting the round in grand fashion, per the PGA Tour:

The back nine was favorable for Haas, as he had four birdies in a six-hole stretch from No. 10 through No. 15 before a bogey on the next hole pushed him back into a tie for sixth place. 

Though Kelly is tied for the lead, this could turn out to be a missed opportunity for the 49-year-old. He was eight under par through 13 with his two top competitors off the course, but he couldn't create any separation down the stretch. He hasn't won a PGA Tour event since the 2009 Zurich Classic of New Orleans, so he probably won't be complaining about being in the mix after Round 1. 

This is uncharted territory for Overton, who has yet to win on the PGA Tour since turning pro in 2005, and the 28-year-old Lahiri has just two wins on the European Tour. 

As if that pressure isn't enough for those three players, the massive cluster of talent behind them will pose additional problems. Former PGA Championship winner Jason Dufner is in the mix after posting his lowest score of the early season (64) thanks to putts like this, per the PGA Tour:

It's been a struggle for Dufner lately, as he hasn't won since the 2013 PGA Championship and had only two top-10 finishes in 21 events last season.

Despite the recent issues for Dufner, Sobel is sensing big things for the 38-year-old in 2016:

Early-season tournaments can serve as a barometer of things to come. Last year, Jason Day carried a February win at the Farmers Insurance Open to four more victories, including the PGA Championship. 

While there's a long way to go this year before making big proclamations about what will happen, Dufner looks better now than he did at any point in 2015. He's going to have to keep it going with a crowded field fighting for the top spot heading into Round 2.

Stats per PGATour.com.