Nick Hardy and Davis Riley withdrew from this week's PGA Tour stop, the Mexico Open at Vidanta, on Monday after winning the Zurich Classic of New Orleans on Sunday.
No reason was given for the withdrawals.
It marks the first time since last November that a PGA Tour winner withdrew from an event he was scheduled to play the following week, Golfweek reported.
The only team-based tournament on the PGA Tour schedule, the Zurich Classic uses a four-ball (best-ball) format in the first and third rounds and foursomes (alternate shot) in the second and final rounds.