AUGUSTA - It is with an odd sense of winner’s regret that the defending champion returns to the Masters this week. Hideki Matsuyama is uneasy.

It’s the jacket. He’s rarely worn it, never laundered it, just feared for it.

“I thought about it and it needed to be cleaned but I was so worried that something might happen to it. So I didn’t want to let it out of my sight,” the first Japanese player to win a major championship lamented over his green jacket. “I just spent a year looking at it. I really haven’t worn it that much but I look at it a lot.

“And now, I wish I had worn it more.”

That drew a round of laughter from his press gathering Tuesday. This was a different vibe from the same reserved player who reacted to dropping his final putt last April -- a winning bogey -- as if he’d just finished up a pro-am in Topeka. There is little question his Masters title put Matsuyama on a positive rebound in his 10th year on the PGA Tour, with two more wins (the Zozo, the only Tour stop in his native Japan, and the Sony Hawaii Open) as well as five top-10s in 32 tournaments following Augusta.

Perhaps the best rule of thumb this week is he should be counted on to contend, if he can only stay on the course.

“It’s been a great year with wins at Zozo and Sony,” he said via translator Bob Turner. “Last couple weeks, though, have been a struggle. Hopefully, I can find my game and be a worthy defending champion.”

His chief adversaries have been a troublesome back, which has flared from time to time throughout his career, and a sore neck, which introduced itself five weeks ago during the second round of the Arnold Palmer Invitational. He managed to finish at Palmer but was forced to skip the Players Championship and the ensuing WGC Match Play. He tried to come back at the Valero Texas Open last week but had to withdraw on Friday after shooting a first-round 74.

“Since (the Palmer), it has been a struggle,” he said. “I had a lot of treatment last week, though, at the Valero Texas Open. Monday and Tuesday, I was pain-free, feeling really good. Then woke up Wednesday and the neck was stiff again.”

Augusta National is hardly the place for rehabbing an injury. (Ask Tiger Woods.) The topography alone can be a physical challenge. No one feels better after walking the property for a week.

“As far as golf, besides the injury, I really haven’t been able to hit a full shot, a 100-percent full shot in a long time,” he said. “So that’s still a question. But I feel like the treatment I’ve been receiving is helping, I’m on the road to a full recovery. I still have (Tuesday) and Wednesday and I think by Thursday, I’ll be ready to play my best hopefully.”

He has surprised this tournament before. Look no further back than last April, when he entered the Masters without a single top-10 finish and two missed-cuts in his previous 12 events. Going into the third round three shots behind leader Justin Rose, Matsuyama fired a 7-under 65 for the lowest round of the weekend to take a four-shot lead into Sunday. Both Will Zalatoris and Xander Schauffle took runs at him, Schauffele reeling off four straight birdies to close within two with three holes to play.

But Matsuyama restored the margin and was able to win with a bogey-bogey-par-bogey finish, holding off Zalatoris at one shot back. The impact of his victory still resonates, hitting him most recently last week at the Texas Open.

“It was a little sad because I knew that was going to be the last time that I was going to be introduced (on the first tee) as the defending Masters champion,” he said. “So it kind of made me feel, hey, I need to go out and win again so I can continue that highlight.”

And heck, maybe slip on the jacket once and a while too.