The center has a strained neck after X-rays Saturday night were negative. His status is day to day with the Spurs now trailing 2-1 in their opening round series. Game 4 is Monday night.
McDyess slumped down near midcourt with his teammates surrounding him with 2:56 left on the clock and Memphis up 86-82. Tim Duncan waved to the bench for help, and McDyess was helped to the bench. Then he went to the locker room.
Spurs coach Gregg Popovich spoke to reporters so quickly after the game he said he didn't have an update on McDyess.
"It doesn't look good," he said.