A's Outfielder Chad Pinder Knee'd In Face In Scary Collision During Tigers Game

Scary moment on the MLB diamond Tuesday ... A's shortstop Elvis Andrus hit Chad Pinder in the face with his knee in a violent collision during Oakland's game against Detroit.

Thankfully, both guys were somehow OK.

The horrifying moment just went down in the fifth inning of the A's vs. Tigers afternoon matchup ... when Andrus attempted to leave the infield to catch a short pop-up that was dropping in left field.

Pinder raced in from deep in left to also try to catch the ball -- and as he dove to make the grab, Andrus accidentally hit him with full force.

Video shows Andrus' knee hit Pinder's face hard -- and the two stayed down on the grass for several minutes.

Trainers eventually came out to check on the Oakland duo -- and, wildly, both guys ended up being fine and stayed in the game.