Warren suffered a head injury in the first half of Friday's preseason game against the Utah Jazz.
A fourth-year player, Warren, 24, received five stitches on his head.
The injury occurred when Warren was closing out on defense and collided with a 3-point shooter in the corner. Warren fell and hit his head on a cemented area away from the court. He was taken to the locker room and was ruled out for the rest of the game.
Warren recently signed a four-year, $50 million contract extension with the Suns.
He has missed portions of his three NBA seasons with injuries, including season-ending foot surgery in 2015-16 and a minor head injury last season.
The Jazz won Friday's home game 112-101.