Brooks Koepka withdrew from the Arnold Palmer Invitational after 11 holes Sunday because of a rib injury.

Koepka makes his Masters debut in three weeks and is hopeful that a week off with rest and therapy will help. He is No. 18 in the world with wins in Turkey and Phoenix in the last five months.

He says he first felt discomfort in his back on Friday before posting a 66. He had a trainer stretch during the third round, and it reached a point Sunday where it hurt to breathe and walk. Koepka says the pain after he hit an 8-iron on No. 11 was as bad as he had ever felt on a golf course.

He is scheduled to play the Shell Houston Open after a week off.