Rafael Palmeiro to Play Pro Baseball at 53 Years Old

He's 3 years older than the AARP minimum age, but 53-year-old Rafael Palmeiro is still playing pro baseball -- signing a new deal with an independent league team in Texas!

The 4-time MLB All-Star has agreed to play for the Cleburne Railroaders of the American Association of Independent Professional Baseball.

What's really cool ... he'll be teammates with his 28-year-old son, Patrick!

Palmeiro REALLY wanted to get a shot with an MLB team, but since that didn't happen ... he signed with the Railroaders.

"Nobody gave me a chance to go to spring training," Palmiero said in a text message to the Dallas Morning News ... "so I will just take this path."