Thomas Harley's transition to NHL hockey was always going to be harder than for most other top defensive prospects. 

In junior and minor hockey, the Dallas Stars' rookie defenceman played a different game than most: He was a rover. On a typical shift, you could find him leading the rush, retrieving pucks below the goal-line (his own and the opposition's) and setting up plays all over the ice. He was aggressive and confident; a thinker of the game. 

And while his playstyle generated a lot of mistakes, more often than not, he managed to outscore them. 

While that rover style brought Harley a lot of success in the past — he lined up two productive seasons to end his OHL career with the Mississauga Steelheads and a remarkable first AHL season with the Texas Stars — it also made his first season in the NHL an up and down affair.