Bradley opened with rounds of 71 and 72, and at 3 over he was tied for 41st among the 67-man field, 11 shots behind leader Sergio Garcia.
This is Bradley's first career withdrawal on the PGA Tour, and it stemmed from lingering questions he had over an embedded-ball ruling he received on the 18th hole of his opening round. Bradley took relief under Rule 25-2 for an embedded ball in the grass face of a greenside bunker after conferring with a rules official, but a subsequent conversation with a fan cast doubt for Bradley over whether the ball was truly embedded.
"I just feel withdrawing is the right thing to do to protect the field in the BMW Championship and the Tour Championship next week. It’s eating me alive," Bradley said in a statement. "I didn’t call my fellow competitors for help in the first place and that bothers me. I know the official approved the drop but I just can’t be absolutely sure it was the right spot.”
Bradley was one of three players added to the U.S. Ryder Cup team Tuesday by captain Tom Watson, but it hasn't been a strong week in Denver for any of the selections. In addition to Bradley, Webb Simpson and Hunter Mahan will both begin the third round in a tie for 57th, 13 shots off the lead.
Bradley entered the week at No. 28 in the FedEx Cup standings, but after an early exit he will likely miss next week's Tour Championship, an event he has qualified for every year since 2011. Bradley's season included six top-10 finishes in 26 starts, highlighted by a runner-up finish at the Arnold Palmer Invitational in March.