His manager said McKean was struck at West 86th Street and Broadway in Manhattan around 3 p.m. on Tuesday. He was transported to an area hospital in stable condition and is expected to be OK.
The 64-year-old actor was starring in the Broadway production of the political drama, "The Best Man." However, his injury sent producers scrambling Wednesday to fill his part. Producer Jeffrey Richards said McKean's role will be played by James Lecesne.
"The Best Man," a revival by Gore Vidal, pits two candidates vying for their unnamed party's presidential nomination. The play has been extended twice and is now playing through Sept. 9.
The cast includes James Earl Jones, John Larroquette, Candice Bergen, Kerry Butler, Angela Lansbury, and Eric McCormack. The play has been nominated for a Tony for best revival.
McKean's past Broadway appearances have included "Hairspray" and the Harry Connick Jr. revival of "The Pajama Game." He is best known for his roles in "Laverne & Shirley" and "This is Spinal Tap."
The Associated Press contributed to this report.