Marin still has potential, but will he show it in '12?
Marin Cilic ended the year ranked No. 21, which can be seen as an extreme disappointment or a big positive considering he was mentally all over the place coming into the year. Just two years ago the tall and powerful Croatian looked like he would be the next Juan Martin Del Potro, but he really hit the skids. In 2011, he did pick up his level here and there. He is still only 23, but has not shown a consistent style that will bring him into the top 5. Power is not everything in the men