An auto struck and critically injured an ­11-year-old Brooklyn Thursday when he ran onto a busy street in ­Flatbush, cops said.

The boy and two friends were playing basketball outside PS 399 on 28th Street just after 5 p.m. when the accident occurred.

“He was out playing like any other 11-year-old kid,” said Quasi Reid, whose daughter is on the victim’s basketball team. “He’s a quiet, good kid.”

The driver of the car remained on scene and no criminality is suspected, cops said.