Orioles star Ryan Mountcastle drilled a fan in the face with a home run ball last week ... but he more than made up for it Wednesday night -- gifting the dude a signed bat!!!
The story behind it all is pretty damn funny ... during a June 4 game against the Indians, Mountcastle hit a blast into left field that clanked off of Jake Jones' dome as it crash-landed in the seats.
Jones' failed catch attempt did major damage ... he claimed on Twitter the ball hit his forehead so hard, he had a concussion and needed stitches to repair the damage.