*An ambulance had to cart David Letterman’s stage manager Biff Henderson to the hospital yesterday after a football pass from his boss sent him falling off the stage.

The “Late Show” crew was killing time before the arrival of New Orleans Saints quarterback Drew Brees yesterday by tossing around the pigskin.

At some point, Letterman threw a pass to Biff that had a little more on it than the 63-year-old expected, causing him to tumble into the laps of stunned “Late Show” audience members.

“I caught it,” he declared weakly after his fall.

Biff Henderson is wheeled into an ambulance outside "The Late Show with David Letterman" - Feb. 8, 2010

At first, Letterman quipped, “I can smell a lawsuit.” But he turned grim when Henderson complained he couldn’t move one of his knees, reports the New York Daily News.

“They cut the cameras and the band played for about 20 minutes and that’s how we all knew it was serious,” said audience member Sheva Oliver, 29, from Rockland County.

Brees, the Super Bowl-winning QB, was hung up in Lincoln Tunnel traffic. He arrived as Henderson was being put into the ambulance to Roosevelt Hospital.

“Dave looked upset,” said audience member Fred Kaplan, 63 from The Bronx. “Biff looked alert and waved to us from the gurney.”

Henderson was treated in the ER Monday night and released.