Update, 3:45 p.m. ET

Dustin Johnson has withdrawn from the 3M Open because of a back injury.

The world No. 4 opened with a 7-over 78 at TPC Twin Cities before pulling after the round, his first mid-tournament WD since June 2015.

In an email, Johnson’s manager, David Winkle of Hambric Sports, said that Johnson was experiencing tightness in his back that affected his speed and distance control. After rest and treatment, Johnson “definitely” plans to play the next two weeks, at the WGC-FedEx St. Jude Invitational and PGA Championship.

After a victory last month at the Travelers Championship, Johnson has appeared out of sorts. His consecutive rounds of 80 last week at the Memorial Tournament beat only one player and represented the worst 36-hole score of his career, and he followed it up with another disastrous round in the 3M Open. The lowlight Thursday came on the par-5 18th hole, his ninth of the day, when he dumped three straight balls in the water while trying to reach the green in two. That led to a quadruple-bogey 9 and an outward 42.

Johnson is now 23 over par in three rounds following his victory at the Travelers, his 21st on the PGA Tour. He is a two-time winner at TPC Southwind, site of next week’s WGC-FedEx St. Jude Invitational.

Original story

A new course and a fresh start did not prove to be the answer for a suddenly struggling Dustin Johnson.

Johnson was firing on all cylinders a month ago, winning the Travelers Championship in large part thanks to a third-round 61. But he missed the cut last week at the Memorial in his first start back, and it wasn't exactly close: Johnson carded consecutive rounds of 80 and finished ahead of just one other player who completed 36 holes.

This week marks Johnson's first trip to TPC Twin Cities for the 3M Open, where he teed off as the tournament betting favorite and the highest-ranked player in the field. But things quickly went awry Thursday morning in Minnesota, as Johnson again struggled and posted a 7-over 78.

The round fell apart in a two-hole span, as Johnson started on the back nine and ran into issues at the par-3 17th. His tee shot found the water, leading to a double bogey, and it only got worse from there as he put three straight balls into the water while trying to reach the green on the par-5 18th. That led to a quadruple bogey and an outward nine of 42.

"Hit a great drive on 18 and we only had like 199 (yards) to cover from where I was, 208 flag, it was a perfect 6-iron," Johnson told reporters. "Hit it right at it and never once did I think it was going in the water. That never crossed my mind when it was in the air. Just went in the water, and I hit two more shots in the water, then I hit a good one (from 186 yards to 3 feet), made a tap-in for a 9."

Johnson is now 23 over in three rounds following his Travelers victory, and appears poised to miss consecutive cuts for the first time since June 2017, when he bowed out early at both the Memorial and U.S. Open. Johnson made just his second birdie of the day on his final hole, No. 9, and pointed to his iron game as the culprit for his recent woes.

"I feel like I'm driving it well, but the iron play, first six or seven holes hit it close and then the rest of the day kind of struggled a little bit with iron play," Johnson said. "Kind of the same last week, I just struggled with my iron play and makes it difficult."

Golf Channel senior writer Ryan Lavner contributed to this story.