DeLaet, who turned 38 on Wednesday, dropped out Thursday before play began at the event.
The native of Weyburn, Sask., ended a nearly two-year absence on the PGA Tour in October after a second back surgery.
He has played five tournaments since his return from a back problem, missing the cut in three events and posting a top finish of a tie for 58th.
READ MORE: Graham DeLaet eyes return to PGA Tour
DeLaet, who first earned his PGA Tour card in 2010, finished a career-best eighth in the FedEx Cup standings in 2013, a year in which he landed a spot on the international team in the Presidents Cup.
DeLaet, who is playing on a major medical exemption this year, hasn’t won on the PGA Tour. He has three career second-place finishes.