The 6'6" wide receiver was drafted by the Buffalo Bills after a sensational junior year at Indiana University -- in which he was selected first team All-Big Ten.

Hardy's body was found in a log jam at the Maumee River on Wednesday afternoon -- after a City water filtration plant employee spotted him and called police.

Our sources tell us it appears Hardy had been in the water for several days. Police are investigating.

We're told Hardy's family had reported him missing on May 30.

Hardy had major issues after his NFL career. He was arrested in 2014 for attacking police officers and was later committed to a mental facility.

However, his friends remember him as a nice, outgoing and generous guy who was an incredible athlete.