If you count today, there are only 5 days remaining in the current season of Hearthstone ranked play -- and thus only 5 days remaining to earn your pirate-themed card back. You need only reach rank 20 to earn the card back. As we've mentioned many times before, that isn't too difficult a task. You can't lose stars (or ranking) until you've surpassed rank 20. Until then, you have nowhere to go but up. The impending weekend is a good opportunity to do it.