World number one Dustin Johnson sits three shots off the lead following the opening round of the AT&T Byron Nelson in Texas.

The American, who is stepping up his recovery from the back problem which ruled him out of last month’s Masters, carded 67 at the Four Seasons Resort and Club in Dallas to finish the day three under par.

The competition is his third since the injury after he finished tied for second at the Wells Fargo Championship and was joint-12th in last week’s Players Championship.

Johnson’s compatriots James Hahn and Ricky Barnes hold the joint overnight lead on six under, while Matt Kuchar, Jason Kokrak, Cameron Tringale and Venezuelan Jhonattan Vegas are all two strokes off the pace. Jordan Speith is a shot behind Johnson on two under.

Defending champion Sergio Garcia, who also won the tournament in 2004, has plenty of work to do after he hit three bogeys during a first-round 73 which leaves him three over, though Ian Poulter is on even par.