It all went down Monday night in the fifth inning of the Cleburne Railroaders' tilt with the Fargo-Moorhead RedHawks -- when Palmeiro hit a BOMB off a pitcher 25 years younger than he is.
Remember, the former Baltimore Orioles All-Star signed with Cleburne earlier this month in what seemed like a PR stunt for Rafael to get some quality time with his son, Patrick, on the baseball diamond.
But, Palmeiro's been ballin' despite being about three decades older than everyone on the field, recording two hits in his third game of the season on Monday.
Cleburne ended up losing 4-3 in extras ... but Raffy and the boys will be back at it in Game 2 of the series Tuesday night!!