(Reuters) - Rory McIlroy and Jordan Spieth were ranked one and two in the world heading into last year's PGA Championship, but they return this year almost as after-thoughts, overshadowed by a wave of hotter rivals who have grabbed the limelight.

Not that anyone is writing off the pair from contending at Baltusrol in New Jersey this week, but their status as underdogs underlines how quickly the sporting landscape can change.

World number one Jason Day, U.S. Open champion Dustin Johnson, and British Open duelists Henrik Stenson and Phil Mickelson are more the focus of attention, leaving McIlroy and Spieth searching to find the missing ingredient needed to regain their previous greatness.

Not that either is too far off top form, but there is a fine line in golf between lifting a trophy and finishing in the pack.

McIlroy, winner of four major championships including the 2012 and 2014 PGA Championships, feels more at home at Baltusrol than at Royal Troon, where he tied for fifth, a distant 16 strokes behind winner Stenson nine days ago.

The Northern Irishman is probably the best driver in the world when he is on song, but links courses such as Troon that often do not necessitate hitting a driver do not always play to his strength.

McIlroy admitted he could not have envisaged matching Stenson's record winning score of 20-under at Troon, though his task was not helped by the bad luck he had to be on the more difficult side of the draw.

"Baltusrol, it's more of my type of golf I guess, and I feel like I can really do well this week. I feel like my game is in good shape," McIlroy told reporters on Tuesday ahead of Thursday's opening round.

"I had some really good practice sessions with my coach, Michael Bannon last week. I feel like I'm swinging it well. I'm hitting it good. Every aspect of my game, I'm very comfortable with.

"So combine that with the layout of the golf course here, and I feel like this is my best chance this year to win a major."

Spieth also thinks he is on the verge of firing on all cylinders, after recently deciding to just grip it and rip it, to use the old John Daly line, rather than over-thinking things.

"I've been getting a bit too frustrated at times but recently I've gotten back to kind of the gunslinger, the way that I grew up playing, which is just step up and hit it," the Texan said on the eve of his 23rd birthday.

"I have more confidence in my mid-to-long-iron play than I did last year. Short game has gone down just a bit. I'm working hard on it."

Spieth, who won the Masters and U.S. Open last year and came close at the British Open and PGA Championship, is focusing on a long term goal of winning all four modern majors.

"My goal has changed now to trying to win a career grand slam, and this would be a fantastic time to grab a third leg," he said, observing that he was still young, though "younger today than tomorrow."

(Reporting by Andrew Both in Cary, North Carolina; Editing by Frank Pingue)