Allan Mitchell of The Athletic did a deep-dive into Klingberg's last five seasons and what he found defensively warranted Klingberg to be listed as one of the top-five riskiest signings this off-season. Klingberg's defensive struggles are no secret, but he played much better following a trade to Minnesota at this past season's trade deadline. Other than that however, Mitchell identified that the last time Klingberg performed well in a top-pairing role at five-on-five was the 2018-19 season with Dallas. Outside of the 2018-19 season when Klingberg played almost 40 percent of his time against top-six forwards, the only other time he performed well against top-six forwards was the 2020-21 season, but he only played 25 percent of his time against them.
The Leafs are a much better defensive team than Anaheim and Minnesota and the theory is that the Leafs are hoping their defensive structure will help hide some of Klingberg's defensive woes. However, the signing is still risky. If things don't start well for Klingberg, he could find himself on the bottom pairing or even out of the lineup very quickly.