Will jet-lag be a factor in this week’s WGC-FedEx St. Jude Invitational?

Just under a quarter of the field played at the Olympics in Japan and will have to deal with a 14-hour time difference in Memphis.

Patrick Reed's call-up to Team USA came so late that he teed off in the first round of last week's men's Olympic golf tournament less than 24 hours after arriving in Japan following his long-haul flight from the United States.

In the circumstances, shooting a 68 in round one was impressive given that his body clock was so out of whack.

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There was speculation in the commentary box that Reed could now be considered a genuine contender after he'd come through the worst of it. Surely he'd feel more and more comfortable and adjusted as the week went on.

However, one of the experts behind the mic, Alison Whitaker, offered a different take.

She stuck her neck out and said Reed would likely struggle on day two. Speaking from experience as a worldwide traveller, the Aussie said adrenaline had helped Reed get through the first round but jet-lag would kick in the following day.

It proved a prescient comment.

Reed took a step back in round two, firing an even-par 71 and dropping from tied 12th to tied 24th. He fell further to tied 38th on Saturday before, perhaps fully on Japanese time, came back to life with a closing 65 to end the week tied for 22nd.

Now, along with 18 other of the 66-man field in Memphis, he flies from Japan to Tennessee and has a 14-hour time gap to deal with.

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So should we strike a line through all the Olympians - including gold medal winner Xander Schauffele, Rory McIlroyJustin Thomas and Collin Morikawa - when they tee it up this week?

Or is that a dangerous policy?

Instinctively, it seems that jet-lag has to be a negative and very recent evidence shows Dustin Johnson finishing a promising tied eighth in the Open Championship at Royal St George's before jumping on a plane and missing the cut at the 3M Open in America five days later.

DJ also seemed affected last year when flying back from the Saudi International to Pebble Beach, a venue where he's won twice. Johnson was runner-up in Saudi but looked subdued when only tied 32nd at Pebble as he battled another big time difference.

However, only two months ago, Norway's Viktor Hovland flew from the the West Coast of the United States to Germany - a nine-hour time gap - and waltzed off with the BMW International Open title.

McIlroy won the Irish Open after jetting in from the States, Jon Rahm landed the 2018 Spanish Open straight after the Masters and there are numerous other examples of players winning a week after crossing the Atlantic.

Perhaps it's player specific and some adjust better than others.

Or maybe the direction of travel and time gap makes a difference.

Going east to west and contending with a 14-hour time differential must surely be a factor for those taking part at TPC Southwind this week.

Perhaps, though, the trick is to back one of the Olympians for first-round leader when they get by on adrenaline but be wary of betting on them to win overall.

Alternatively, it could pay to look to the match betting markets and support a player who didn't take part in the Olympics against one who did.

One thing is for sure, this will be an interesting case study.

Defending champion Thomas and Olympic gold medal winner Schauffele were asked about their sleep patterns after the trip to Japan when they arrived for Tuesday's press conferences in Memphis.

Here's what they said.

Justin Thomas quotes

"This morning I slept until my alarm at 6:30. I would have loved to sleep as late as I wanted, but I knew just doing this before that the sooner you get your body clock adjusted to where you are, the better.

"I got in bed at 8:30 last night and I woke up at like 11:30 or 11:45 with all my lights on so I didn't even make it long enough to turn my lights off, so I was clearly exhausted.

"Yeah, I woke up like one point in the middle of the night, was awake for probably 10 minutes, but I wasn't too pleased when my alarm went off at 6:30 this morning. It was all right once I got moving, but I'm starting to drag a little bit right now."

Xander Schauffele quotes

"We took off at 11:50 and we landed essentially the same time. We landed maybe 9:30, 10:00, 10:00 a.m. yesterday.

"Yeah, I'm good. I think a lot of what I did sort of in recovery last week was to make sure I was fresh for this week.

"I'm going to be as fresh as I can be, I'm going to do everything I can this week to sleep enough, to eat right, make sure my mind is okay. But I think playing really well and obviously having a gold medal is just feeding my energy.

"One, I'm really excited to get back home to the west coast, but two, you want to win each and every week and now that I finally got this taste of winning and being able to win from up front, that's why I think all of us compete. That's the rush we really chase and it does feel good and it's really rewarding to pull off and I'm ready to get back to work."

READ MORE: World Golf Championship St Jude Invitational: Punter's pointers

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