WASHINGTON (AFP) -- Reigning US Open champion Wyndham Clark suffered a back injury in a gym workout and is questionable for this week's PGA Houston Open with his planned Masters debut only two weeks away.

World number four Clark, who won last month at Pebble Beach and finished second to top-ranked Scottie Scheffler this month at Bay Hill and The Players Championship, hurt himself while hoisting weights in Scottsdale, Arizona.

"I just got caught in an awkward spot doing a lift and back went," Clark said on Wednesday, March 27. "It's not something that happens regularly, but it happened and you live and you learn.

"I'm trending in the right direction. I'm hitting it or feeling stronger and more mobile every day."

Clark was confident of teeing off in Thursday's opening round at Memorial Park Golf Course with the 30-year-old American's first Masters set for only two weeks later at famed Augusta National.

"I was in pretty bad shape yesterday, but fortunately I have a great team that has gotten me to be able to swing and hit," Clark said

"I was only really able to chip and putt, then I did a bunch of rehab and I was able to hit balls today. So just in a short time I've improved a ton and I think I'll be ready for tomorrow.

"I'm going to give it my best effort and hopefully I can play and compete. If not, I've got to get ready for tournaments to come after this."

Also preparing for the annual April showdown at Augusta National is Scheffler, who this week will try to become the first player since Dustin Johnson in 2017 to win three consecutive PGA Tour starts by winning his final Masters tuneup.

Scheffler, the 2022 Masters champion, hopes to avoid the same Masters fate that Johnson, suffered seven years ago after three wins in a row.

Johnson, now with LIV Golf, was a heavy 2017 Masters favorite but he fell down a staircase at a rental home and withdrew from the event.

In 15 seasons, only Tiger Woods, Rory McIlroy and Johnson have managed the hat trick, but Scheffler says such things rarely enter his mind.

"I don't really think much about that kind of stuff," Scheffler said. "I had a good rest week at home last week. I was pretty worn out after Bay Hill and Players so it was nice to get home and just relax.

"I didn't do nearly as much practice as I typically would have in the last week, so coming in shaking off a little bit of rust the last couple days. But game feels like it's in a good spot, so I feel rested and ready to go this week."

Clean-shaven Scheffler

Scheffler shocked some by shaving his beard during the time away.

"My beard got so long that it became work," Scheffler said. "Last week I got a haircut and I was thinking about trying to trim it and I didn't really know how, so I just shaved it."

The 27-year-old American is focusing on shotmaking and rounding his game into prime form before trying for his second green jacket in three seasons.

"It will be good prep seeing how my game is going into the Masters," he said.

"I want to approach this week with a good attitude, hit good shots. As far as what I want to see out of my game, I'm going into the tournament hoping to play well so that would be a good result, but at the end of the day I'm focused on attitude and executing shots and stuff like that."