LeSean McCoy: I'm No Herschel Walker ... I Only Box For Fun

LeSean McCoy is making one thing clear ... he only boxes for fun ... saying the chances his newfound pugilistic hobby turns into a second career a la Herschel Walker are about ZERO.

We got Shady out at LAX and asked him what's behind his sudden interest in getting hit in the head OFF the football field ... and taking up the sport of boxing.

Shady told us he's interested in getting his hands right, and loves the cardio, but as far as pulling a Herschel and hopping into the ring professionally?

HELL NO.

Check out the clip!