The foreboding photo shows a shadowy figure (we're assuming it's TB12, but who knows at this point) walking in the tunnel at a stadium. It's dramatic as hell.

But the big mystery -- is Brady walking IN to the tunnel, or is he walking OUT to the field??

Depending on the direction, it could be bad news for the Pats -- there have been rumors Brady is ready to move on to another franchise ... and this may be a way for him to soften the blow for New England.

Remember, we spoke with Pats owner Robert Kraft last week ... and he said "the plan" was to bring Brady back next season.

TB12 is a free agent ... but that doesn't necessarily mean he's going anywhere. The dude very well could be messing with all of us for fun.

So we gotta ask ...