By Larry Fine

SPRINGFIELD, New Jersey (Reuters) - Masters champion Danny Willett's game has struggled since his unlikely win at Augusta National, but the Englishman says he is ready to get back on track at this week's PGA Championship.

Since winning the green jacket in April for his first major, the 28-year-old Willett has tied for 37th at the U.S. Open, tied for 53rd at the British Open, missed the cut at the Players Championship and had some poor finishes on the European Tour.

"It's settled down a bit now," Willett said about his post-Masters euphoria and subsequent hangover. "We are trying to get back down to work and knuckle down because we have got a very important second half of the season coming up."

His upcoming stretch, which includes the Aug. 5-21 Rio Olympics and Sept. 27-Oct. 2 Ryder Cup, starts with Thursday's opening round of the PGA Championship at Baltusrol.

"It's time to move on a little bit from what we did in April. It was fantastic and yeah, it's changed my life, but we need to get back to the kind of form that we took into that week and hopefully then move forward," said Willett, adding that his form is rounding back into shape.

"We've had a couple of good weeks' work. Coming in here feeling pretty good. Got the family and stuff with us. Hopefully we are all set to try to compete again in the last major."

Willett said this year's major winners showed that golf's blue riband events did not strictly belong to the so-called Big Three from the start of the season in Jason Day, Jordan Spieth and Rory McIlroy.

"The winners that you've got this year just go to show that you it's been so varied," said Willett.

"Obviously Henrik (Stenson), being 40 and finally capturing a major, which is surprising it's his first because of how good of a player he is," he said of the Swedish winner of the British Open."And obviously Dustin (Johnson) has come so close over the last five or six years, to finally polish one off (at the U.S. Open)."

Then there was Willett himself, who came to Augusta ranked 12th in the world but left wearing the green jacket after taking advantage of Spieth's shocking collapse with a magnificent round.

"It just goes to show the strength and depth throughout golf at the moment," the world number nine said.

"It just goes to show on a week-to-week basis that if anyone who is really there pitches up with their A Game, they have got a good chance of winning."

(Editing by Frank Pingue)