New York Islanders defenseman Matthew Schaefer captured the 2025-26 Calder Memorial Trophy through a historic rookie campaign that produced 23 goals and 59 points in 82 games while leading all first-year players in ice time. Selected first overall in the 2025 NHL Draft, the 18-year-old blueliner set multiple age-related benchmarks, including the most goals by an 18-year-old defenseman and the first unanimous selection since Teemu Selanne in 1992-93. Trader consensus reflected in the 100% implied probability for Schaefer stems directly from this production and the Professional Hockey Writers Association ballots that awarded him every first-place vote. Gabe Perreault’s late-season surge with the Rangers generated minimal residual support at 0.1%, but realistic challenges to the outcome remain limited to an unprecedented administrative reversal after voting concluded.