No one in NY Giants history will EVER wear the #10 again ... the team just announced it's honoring Eli Manning by officially retiring his old jersey number in September.
The Giants say the ceremony will go down on Sept. 26 ... and the team says it'll also put the former star quarterback in its Ring of Honor as part of recognition that day as well.
"It's a great honor and just an unbelievable feeling," Manning said after the Giants broke the news Monday. "I don't know what the emotions will be that day.