Doug Martin- Rookie season a fluke?

This is the second year in a row that I've drafted Doug Martin, hoping he would replicate the incredible season he had as a rookie... and this is the second year in a row he's been disappointing. Now, I understand he's been battling injuries, that is a part of the equation that can't be controlled. But when he's been on the field, he's been underwhelming and average at best. Was his rookie season just a fluke? Because I just have a feeling he may have hit his peak a bit too soon.