I see Slaf's strength right away. Plus he's huge, you can't teach 250 pounds. But I can't tell you how many time I've seen this type of player suddenly just killing it from one day to the next. I've come to have a bit of a feel for it. One day the player is average. The next day, he's the one player in the NHL I want on my team.
It's happened a bunch of times. For example, Bertuzzi, Johan Franzen, Lucic... I remember in all these cases, I was WTF just happened to this player... It's very different from a pure skill player.