La Quinta, CA (SportsNetwork.com) - Michael Putnam used a big back nine to surge up the leaderboard and shoot a 9-under 63 in Thursday's first round, giving him a 1-shot lead at the Humana Challenge.

Putnam, who has never won on the PGA Tour, has three career victories on the Web.com Tour, two of which came in 2013. In five events on tour this season, Putnam has missed the cut twice and his best finish is a tie for 26th at the Shriners Hospitals for Children Open.

Over the first three rounds, players will alternate between playing the Arnold Palmer and Jack Nicklaus Private Courses at PGA West along with La Quinta Country Club. Sunday's final round will be contested on the Palmer Course.

"You kind of have to forget about it just because we're playing a totally different golf course tomorrow," said Putnam. "That's the only time I'm going to play the Nicklaus so kind of put that out of my memory now and now I'm focusing on the Palmer for tomorrow."

Francesco Molinari, the only non-American in the top 10, finished with an 8- under 64 and he is tied for second with Blake Adams, Mark Wilson, John Peterson and Scott Pinckney. Molinari and Adams played on the Palmer Course, Wilson and Peterson were on the Nicklaus Course and Pinckney played at La Quinta.

Defending champion Patrick Reed (La Quinta) fired a 7-under 65 and he is tied for seventh with Matt Kuchar (La Quinta), Jason Kokrak (Nicklaus) and Steve Wheatcroft (Palmer).

Playing in his first event since withdrawing from last season's BMW Championship, 42-time PGA Tour winner Phil Mickelson carded a 1-under 71 and he is tied for 89th.

Putnam, the 2013 Web.com Player of the Year, started off with three pars from No. 1 on the Nicklaus Course before rolling in his first birdie on the par-5 fourth. He gave that shot back two holes later with his lone bogey on No. 6, but Putnam was on fire from there.

After finishing the front nine with two more gains on seven and nine, Putnam rolled on the back nine by making birdies on every hole except the 11th and 18th, both of which he parred.

Over his final 12 holes, Putnam made nine birdies and three pars. He finished the back nine in just 29 shots.

"Like a light switch and said I needed to make some birdies, so I did," Putnam said about what happened from the seventh hole on. "I played decently solid before that, just made a few mistakes to make bogeys, but then just lit it up coming in."

Molinari, playing the back nine first, made a birdie on 11 and went on to make five straight pars from 12 before he also caught fire. Molinari rolled in five straight birdies from 17, made a trio of pars from four and finished up with a pair of gains on seven and eight to go along with a par on No. 9.

Adams, also starting on the back side, traded a birdie on 11 for a bogey on 12. Much like Putnam and Molinari, Adams went on a run with six straight gains from No. 14. After three straight pars from two, Adams drained a trio of birdies from five. Despite closing with a bogey on nine, Adams remained one shot back heading into the second round.

Wilson, the 2012 champion at this event, started off on fire with an eagle on 13 to go along with birdies on 10 and 11. A bogey on 15 dropped Wilson back a shot, but three straight birdies from 17 got him back on track. From there it was smooth sailing for Wilson as he made six straight pars from two before making a pair of gains on eight and nine to finish strong.

Peterson finished his strong first round with an eagle on eight, seven birdies and a bogey on No. 6. A nine-birdie day for Pinckney helped put his name in the mix as he added one bogey to his round on No. 12.

Mickelson, who won here in 2002 and 2004, had a solid front nine with birdies on three, four and six, but three bogeys and just one gain on the back side hurt him as he finished with a 71.

NOTES: Putnam won the Mexico Championship and the Mid-Atlantic Championship on the Web.com Tour in 2013. He also won the Utah Championship in 2010 ... Like Reed did last year, Putnam carded a first-round 63. Reed went on to shoot 63 in each of the first three rounds ... Wilson has had mixed success so far this season, missing three cuts, one secondary cut and finishing in the top 10 twice in five events.