MLB's Lars Nootbaar Crumples In Pain After Fouling Ball Into Groin, Leaves Game

Painful night at the ballpark for Lars Nootbaar ... the St. Louis Cardinals star foul-tipped a ball so hard into his man region -- he had to leave the game.

The incident happened in the fifth inning of the Red Birds' Wednesday night tilt with the Oakland A's ... when Nootbaar was trying to send a changeup over the outfield wall.

Instead, however, his bat barely got a piece of the baseball as it crossed the dish ... and it, unfortunately, bounced off the ground and ricocheted right into his junk.

At first, the game's announcers believed it had smacked off one of his shins -- but when the replays showed it went directly into his family jewels ... they knew exactly what was going down.

Nootbaar, meanwhile, was in a world of pain ... he writhed on the ground for several moments -- before he somehow got up. He would go on to strike out during the at-bat ... and then leave the game to get all checked out.

It's unclear exactly how the guy is now doing ... the Cards only said afterward he was removed "due to a lower abdomen contusion."

To add insult to injury, Nootbaar's Cardinals lost 8-0.