Usain Bolt seen with mystery stain on his pants while leaving a club with his girlfriend

Usain Bolt has been partying with his woman Kasi Bennett for days now after getting injured at the World Athletics Championships.

The sprinting legend was photographed exiting Liberties night club in London with Kasi at about 4:30 a.m. but something in the photo has caught attention. There's a visible liquid stain on his pants, by his groin. and people are asking; is that...? *coughs* Lol.

See the photo below.