Keyshawn Johnson -- 'I Didn't Sell My House Because of Justin Bieber'

Keyshawn Johnson swears his decision to unload his Calabasas mansion has NOTHING to do with his ex-neighbor-from-hell -- Justin Bieber ... and says there's zero beef between him and the egg-happy pop-star.

The ex-NFL legend went on Jon Marks and Sean Brace's radio show today ... and said he made the decision to leave way before JB turned into Dennis the Menace.

In fact, Keyshawn says he's now rooting for Bieber ... and hopes the guy gets his life back on track.

Either way, things are looking up for Calabasas ... Bieber is now strongly considering leaving the community as well.