R.A. Dickey's new personal catcher is ... David Letterman?

The Mets starter stopped by Wednesday's Late Show to let Mr. Letterman try his hand at catching the knuckler.

"Dave asked if he should wear a mask, and I said he didn’t need to. I brought a cup (too), but he didn’t use that, either," Dickey said.

Watch your back, Josh Thole.