Rory McIlroy, Tiger Woods and even POY Justin Thomas have something to prove in 2018

The annual PGA Tour trek to Maui once signified not only the start of a new year but also a new golf season. The latter is no longer the case because of the PGA Tour's wraparound schedule, which made this week's Sentry Tournament of Champions the eighth week of the season.

Still ...

The collective golf world took a short holiday break. The PGA Tour hasn't played an "official" tournament since before Thanksgiving. Some guys are perhaps a bit rusty, using the two-tournament Hawaiian swing (including next week's Sony Open) to ease back into a competitive mindset. Others -- Jordan Spieth comes to mind -- are typically ready to go at this event.

So while this golf season is well underway, now is a good time to examine some of the bigger storylines for 2018, as the first of 37 consecutive weeks of PGA Tour golf is set to begin in Hawaii. (The next break comes a week before the Tour Championship in September.)

Justin Thomas' encore

The PGA Tour's reigning player of the year is back at the site of one of his five tournament victories from last season, and the constant struggle for Thomas will be to resist the urge to compare where he stands today to that of a year ago.

Thomas not only won five times last season, but he also captured a major championship (the PGA) and the FedEx Cup. If he falls short of doing all that again, does that mean it's a bad year?

"I know I'm constantly going to get reminded of what I did last year versus this year and whether it's better or whether it's worse," Thomas said. "I think the hardest part is going to be staying in the moment and recognizing that it's a new year. It's a new opportunity for great things.''

It helps that Thomas already has a victory this season (the CJ Cup in South Korea) and that he had a long gap between victories last year (from Hawaii until the PGA Championship), which is a reminder that not everything went well all of the time in 2017. There is plenty of room for improvement -- even if the bottom-line numbers do not exactly measure up.

DJ at No. 1

If there is such a thing as a quiet No. 1 in the world, it is Dustin Johnson. He moved to the top spot after winning the Genesis Open in February. But Johnson lost some of his shine because he failed to contend in any major championships in 2017.

Of course, how might things have been different if Johnson had played the Masters? He suffered a freak back injury falling on stairs at his rental home the day before the first round and withdrew. Johnson was coming off three straight victories, including two in World Golf Championship events. He was a prohibitive favorite at Augusta -- and then didn't play for more than a month and didn't win again until August.

Johnson has 16 PGA Tour victories -- the most of any player dating to 2009, two ahead of Tiger Woods during that period -- and he could hold onto the top spot for some time.

The career Grand Slam quest

Three players -- all under the age of 50 -- will have a crack at joining Gene Sarazen, Ben Hogan, Gary Player, Jack Nicklaus and Tiger Woods in winning all four major championships in a career: Rory McIlroy at the Masters; Phil Mickelson at the U.S. Open; and Jordan Spieth at the PGA Championship. It is the first time since 1989 that three players under age 50 have been in this position; then it was Lee Trevino (Masters), Raymond Floyd (The Open) and Tom Watson (the PGA).

McIlroy has set up a beefy early schedule to give himself a better chance to contend at the Masters. Mickelson will return to Shinnecock for the U.S. Open, where he had one of his six runner-up U.S Open finishes the last time it was held there in 2004. And Spieth gets a second crack at the slam when he tries to win the PGA at Bellerive.

How do JDay and Rory respond?

For the first time since the inception of the Official World Golf Ranking in 1986, the No. 1 and No. 2 players fell out of the top 10 by the end of the year. The fact that Jason Day (1) and Rory McIlroy (2) did not win at all in 2017 was at the crux of the problem.

Why that happened can be analyzed and debated.

Day has admitted that getting to No. 1 in 2015 and again in 2016 took a fair bit of steam out of him. He ended 2016 withdrawing from two tournaments with back injuries and never returned to form in 2017. A playoff loss to Billy Horschel at the Byron Nelson was his closest brush with victory. How he rededicates himself this year will be of keen interest.

McIlroy's woes can be traced more to injury. He suffered a rib fracture playing in his first tournament of the year in South Africa, where he lost in a playoff. He was out for nearly two months before a promising return saw him contend several times. Then came his spring wedding and another injury -- which he said was a result of overdoing it trying to get his game ready again. Rust was a problem at the U.S. Open, then he missed consecutive cuts in Europe; and before you knew it, McIlroy was shutting it down without a win. He vowed to get healthy and be ready for 2018, and he has announced an ambitious schedule that begins in two weeks in Abu Dhabi.

Phil's Ryder Cup quest

Phil Mickelson will turn 48 during the week of the U.S. Open -- and 48 happens to be the oldest that any player has won a major championship -- but he is not relenting to age, especially as it pertains to the Ryder Cup.

Mickelson has made it a priority to be on the U.S. team that travels to France in late September. He has never failed to be part of any U.S. team dating to 1993 -- the last time the U.S. won in Europe -- and has made every U.S. Ryder Cup team along the way without needing a captain's pick.

Given his big behind-the-scenes role over the past few years, Mickelson is determined to be part of a potential U.S. win in Europe. Can he get it done? The points process began with the majors and WGCs in 2017, and Mickelson is 19th in the standings. But there is a long way to go, and he'll get started on his quest in two weeks at the CareerBuilder Challenge.

No viewer call-ins

A big rules change was announced last month and goes into effect this week: rules officials at tournaments around the world will no longer accept calls or emails from those watching on television citing possible violations. To be technical, it goes down as a local rule in 2018, with full inclusion in the 2019 rules book when a substantial overhaul of the rules goes into effect. That doesn't mean rules violations spotted on TV can't be used, but it must come from a rules official watching a monitor. And any kind of dispute can still be settled by looking at video afterward.

Among those happy with the news was Tiger Woods, who had two very high-profile video reviews in 2013.

"I was excited to hear the PGA Tour has changed its policy on television viewers calling in about rules infractions," Woods said on his website last week. "For some time, I have felt the rule was unfair because not everyone is on TV for the same amount of time. Golf is different than most sports where you have numerous officials watching every play all the time. It's up to us as players to police each other and ourselves. Players inadvertently make mistakes, but what happened to Lexi Thompson at the ANA Inspiration and Dustin Johnson at the U.S. Open (in 2016) was ridiculous. Both handled it extremely well, but it's just not fair. Our game has an enormous amount of integrity and we should rely on that."

Schedule

Sometime this summer, PGA Tour commissioner Jay Monahan will announce a 2018-19 schedule that promises to look much different than what we have seen for the past decade.

The PGA Championship is moving to May, meaning the Players Championship is moving back to March -- where it was through 2006. And that means something has to give. Three other Florida events are on the March schedule, as well as the WGC-Match Play. Preceding them is the WGC-Mexico Championship.

To finish the FedEx Cup playoffs by Labor Day, more changes are necessary. The playoffs are expected to be reduced from four events to three. At least one summer event is expected to move to the fall.

Is this Rickie's year?

For all his acclaim and success, Rickie Fowler has but four PGA Tour victories, the last coming at the 2017 Honda Classic. He has three more international titles, including wins in Abu Dhabi and Scotland. He has been a big part of Ryder Cup and Presidents Cup teams. He is ranked seventh in the world.

Is this the year he wins a major championship?

Fowler has contended several times. He had two top-5 finishes in 2017's majors. He was top 5 in all four majors in 2014. There have been chances.

A final-round 61 at the Hero World Challenge last month was an indication of the strength of his game. It will be intriguing to see if Fowler can follow through and hoist a major trophy.

Tiger's return (again)

Any prognosis for 2018 comes with a good bit of caution as it relates to Tiger Woods. The injuries have been too numerous and debilitating over the past four years to think otherwise.

But his appearance last month at the Hero World Challenge gave plenty of reason for optimism -- guarded, but optimism nonetheless.

Woods looked strong and powerful. He played well for someone who had been out for 10 months, underwent a serious back surgery in April and had only about a month to prepare. What can he do with more practice and preparation?

So far, Woods has committed to the Farmers Insurance Open later this month and the Genesis Open, which is three weeks later. Whether he adds the Honda Classic -- a week after Genesis -- will likely depend on how he responds.

"I would love to play a full schedule in 2018," he wrote on his website last week. "What that entails, including back-to-back events, I don't know. I just have to continue to work on my body and game and see where I pan out."

It is believed that Woods will play the Farmers Insurance Open at Torrey Pines later this month. Might he consider a more user-friendly venue the following week at the TPC Scottsdale, instead?

He also is expected to play the Genesis Open at Riviera in February. The Honda Classic, near his home in Florida, follows Genesis. So would he then play two weeks in a row?

"This is all uncharted territory," he said.

For Woods to have success, he needs to be able to properly practice and prepare. The time away from tournaments is just as important as what occurs during them. And he'll need some patience too.

Kick it off at Kapalua

The goal of every PGA Tour player is to be in the field for the Tournament of Champions -- or at least qualify for it. That means winning in the previous year. But there is this cautionary tale: Only nine of the 32 players who were in the field in 2017 are back to tee it up this week. How many will return in 2019?