In the early days of the NHL, Harry Cameron had four top 10 finishes in 1917-18, 1918-19, 1920-21, and 1921-22; Georges Boucher had three straight between 1921-22 and 1923-24. Sprague Cleghorn and Ken Randall each had two top 10 finishes, both in 1918-19 and 1921-22.
Later on, Red Kelly had top 10 finishes in 1950-51, 1952-53, 1953-54.
Potvin finished top 10 twice, and was a single point off in 1975-76.
The other defensemen to finish in the top-10 of the scoring race are Eddie Gerard (1917-18), King Clancy (1923-24), Tom Anderson (1941-42), Bill Gadsby (1955-56), Pierre Pilote (1964-65), Doug Mohns (1966-67), Brad Park (1973-74), Ray Bourque (1986-87), Al MacInnis (1990-91), Brian Leetch (1991-92), and Brent Burns (2016-17).
Karlsson would thus join Harry Cameron, Georges Boucher, Red Kelly, Bobby Orr and Paul Coffey as the sixth NHL defenseman to make the top-10 scorers three times, if he does so.