Dustin Johnson withdrew from the Valero Texas Open on Monday, the PGA Tour announced via Twitter.

The world No. 1 had committed on Friday to play the event which proceeds his Masters title defense. No reason was given for the exit. He will be replaced in the field by Ryan Brehm.

Johnson won the 2020 Masters Tournament with a record 20-under-par total. The event was rescheduled to November because of the coronavirus pandemic.

Johnson hasn't won on Tour since, but did capture the European Tour's Saudi International in February. He has one top-10 in five Tour starts this year, failing to get out of pool play in last week's WGC-Dell Technologies Match Play.