Dustin Johnson withdrew from the 3M Open after his first round, citing a back injury.
The American battled to a seven-over 78 in the opening round at TPC Twin Cities in Blaine, Minnesota on Thursday.
Johnson later withdrew from the tournament due to a back injury, the PGA Tour confirmed.
The world number four won the Travelers Championship last month before missing the cut at the Memorial Tournament.
Johnson's injury concern comes just two weeks before the start of the US PGA Championship – the first major of 2020.