The contract switching to a one way deal may indicate that the Leafs are planning to make Woll a full time NHL backup in the near future. Likely meaning that at some point,
Jack Campbell or Petr Mrazek could be moved out. It could also be the Leafs making sure that they have an option in the back-up slot should Campbell walk away in free agency. Either way, having a goalie capable of playing NHL games at such a low cap hit is an excellent thing for the Leafs.