Saquon Barkley Helps Giants Fan Attempt To Get Ex Back With Autograph

Saquon Barkley might've just saved a teenager's relationship with his ex-girlfriend ... all by putting his John Hancock on a poster.

For real.

Here's the deal ... Kareem Reyad went out to New York Giants practice Thursday at Quest Diagnostics Training Center in New Jersey to urge the 26-year-old running back to help him get his girl back after the two had split late last year.

Wearing a No. 26 Barkley jersey, Reyad wrote on a sign, "Saquon my ex will take me back if you sign this" ... and he flashed it throughout the NYG workout.

Turns out, Saquon noticed it ... and following the practice -- he actually helped Reyad out!!

Barkley autographed it ... and then posed for a photo with the guy -- and get this, Reyad told TMZ Sports afterward he thinks it all might work out now!!

The Rutgers University student says ... he and his GF initially broke up in September due to college -- but she's always been a huge Saquon fan, and he has a feeling the two-time Pro Bowler's autograph might be enough to bring them back together.

The 19-year-old said he's going to drop the sign off at her house soon ... with the hopes that it all works out.

"I have nothing but love for this girl," he said.