Former NFL Star Jamal Anderson -- The Bank Took My Mansion

Former NFL star Jamal Anderson took a beating on his Georgia mansion ... TMZ has learned his primo crib was sold off at a foreclosure auction ... for $225,000 LESS than what Jamal paid.

Jamal -- who played for the Atlanta Falcons from 1994 to 2001 -- bought the MASSIVE 10-bedroom, 9-bath crib way back in 1999 (when he had an NFL contract) for $1.225 million.

According to official records, Anderson defaulted on his mortgage ... so the bank foreclosed the home and recently sold it at auction for an even $1,000,000.

It was a STEAL for the buyer ... the pad is over 6,000 square feet, sits on 2 acres and is rockin' a separate guest house, arcade room, media room, pool and spa.