Seems like the rapidly-fading New England Republicans have a host of political juggernauts in the Senate. I would normally caution against this as an internal poll, though I really don't see the point in leaking a poll showing your side getting massacred in a race that you would win easily against any other candidate.
it might be a "Don't bother" move. I.e. the Democrats have basically given up trying to beat him, and are making that public so Liberals don't pressure them to do so when they know its going to be close to impossible.