Rob Gronkowski, Aldon Smith ... now Percy Harvin!?!?
The former Super Bowl champ and ex-1st-round pick is gunning to become the next surprise NFL un-retirement ... saying he's training with an Olympian for a 2020 comeback!
"I'm ready to return to the NFL," Harvin told ESPN's Josina Anderson. "I thought I was done, but that itch came back. I’ve been training w/a former Olympian. My body is feeling good. Mentally I’m better. My family is good. The timing is right.”
31-year-old Harvin last played in the NFL for the Buffalo Bills in 2016 .