Jets Receiver -- Overjoyed to Give Tim Tebow #15 -- The Number's CURSED!!!

Tim Tebow's new teammate wasn't being generous when he willingly gave Tebow his #15 jersey -- Tebow's old number on the Broncos -- because it's CURSED ... at least according to its former owner.

In case you didn't know -- #15 on the Jets was previously worn by wide receiver Scotty McKnight, who was re-signed by the Jets just two days ago.

But Scotty doesn't have fond memories of wearing the jersey -- getting minimal playing time during last year's preseason, and eventually getting bumped to the Jets practice squad where he tore his ACL.

Now, sources close to Scotty tell us, the WR is pumped to start fresh with a new number -- and sees Tebow taking the jersey as a blessing ... relieving him of his bad luck

Good news for Hayden Panettiere too -- because she's dating the guy.