As mentioned, there were expectations for him to be a top blueliner on the Leafs, along with former young prospect Rasmus Sandin, who was also envisioned as a top blueliner for the team. Niemela was mainly praised for the way he moves the puck as a defenceman. He also showed great vision and was able to make a pass whenever it was possible. He was also seen as someone who wasn't afraid to take a shot on goal and walk into the slot.
Niemelä, 23, was a third-round pick by the Maple Leafs in 2020 and quickly became one of the organizations most promising prospects with a strong season as a teenager in the SM-Liiga in Finland with Karpat. Niemelä became a top-ranking name in the Leafs system at the 2021 World Juniors when he was named top defenceman at the tournament with eight points in seven games as Finland went on to win the bronze medal.