Pirates Minor Leaguer Attacks Pitcher In Insane On-Field Brawl

One of the best prospects in the Pittsburgh Pirates' farm system was so pissed off over being hit by a baseball Saturday -- he straight-up charged the mound and attacked the pitcher who threw it.

The wild scene all went down in an Arizona Fall League game in Scottsdale ... when Bucs outfield prospect Canaan Smith-Njigba was drilled in the upper shoulder area by a pitch from Red Sox prospect Josh Winckowski.

In video of the play, captured by Baseball America, you can see Smith-Njigba immediately ran at Winckowski after being plunked -- and started throwing punches.

The guy appeared to land three huge right hands ... before the rest of the players on the field dove into the scrum to break things up.

Both Winckowski and Smith-Njigba were ejected for their roles in the fight ... though no word yet on if they face further punishment.

As for why Smith-Njigba was so irate over being hit ... the two teams had played Friday night -- and one of Smith-Njigba's teammates had been hit in a similar fashion during that game.