Maybe they just couldn't fit it in anywhere else (my guess is either The Originals or iZombie lost their slot to Supergirl's late addition to the line-up), or it was always planned because the ratings weren't what they hoped for? I'm surprised because obviously with Reign and The 100 those shows always come mid-season and its expected, but there was never any hint that iZombie was getting cut back, it aired with the CW's other shows last year and had 18 episodes, so this does feel like the network is now downgrading them for whatever reason