A pro soccer player could be facing discipline from his league ... after he straight-up grabbed his opponent's penis TWICE in a disturbing in-game incident that was all caught on video.
Here's the deal ... on Saturday in England, Preston North End FC player Darnell Fisher was trying to guard Sheffield Wednesday's Callum Paterson during a corner kick in the second half.
Video of the play showed Fisher got super close to Paterson ... and then Fisher suddenly grabbed Paterson's junk.
Paterson was clearly upset by the move -- he looked over at the ref to see if the official was going to say something to Fisher -- and that's when Fisher cupped Paterson's genitals yet again.