Seahawks' Derrick Coleman -- I Can Prove I Wasn't Drunk ... In Post-Arrest Video

Seattle Seahawks fullback Derrick Coleman made a video just 3 hours after his frightening 2 car crash Wednesday to prove he was NOT drunk or high ... and it involved reciting his ABC's.

Coleman -- who is legally deaf -- was arrested for vehicular assault and hit and run in Bellevue, Washington after allegedly leaving the scene of a crash in which the other driver sustained serious injuries.

Coleman's lawyer Stephen Hayne flipped on a camera and began his own unofficial field sobriety test -- which included asking Coleman to recite the alphabet WITHOUT singing.

We're told Coleman is being released from jail sometime today. He's been suspended from the Seahawks, but hopes this video will help in his effort to get back on the team.

As for what caused the crash or why he left the scene -- so far, Coleman and his lawyer have not said, though his agent has suggested Coleman may have fallen asleep at the wheel.