Popular NCIS alum Michael Weatherly is returning to TV in a new streaming spinoff of the hit crime-busting franchise — but spies say cast members at the original CBS show are terrified he’ll knock them off the air, RadarOnline.com has learned. “Ratings for the main show have dropped this year, and some of the stars are afraid bringing back Michael in a new format will make their show obsolete,” revealed a TV industry insider while other sources cast doubt upon the claims. The new show, NCIS: Tony and Ziva, is set in Europe. The action-packed show follows Tony DiNozzo and Ziva David after they …