Brian Campbell withdrew from the Travelers Championship before the start of Thursday's first round due to a shoulder injury.
The winner of the Mexico Open in February, Campbell joined Corey Conners, who was forced to withdraw from the tournament due to a wrist injury suffered during last week's U.S. Open.
Campbell, 32, was replaced by Davis Riley in the field.
The Travelers is the final of eight signature events in 2025, featuring a $20 million purse.
Campbell rose to 97th in the Official World Golf Ranking following his first PGA Tour victory in Mexico, but has struggled to build on that triumph. His best finishes in 12 events since are a pair of T32s, including at the Masters.
In his past three starts, Campbell has a pair of missed cuts sandwiching a withdrawal from the Charles Schwab Challenge.
