In the 1985 version of his annual Baseball Abstract, sabermetrics pioneer Bill James introduced the "Keltner List" as a method of assessing whether players belong in the Hall of Fame. The Keltner List, a series of questions summarizing a player's career, has been adopted by basketball.
Neil Paine of FiveThirtyEight even used it in a series for ESPN Insider a couple of years ago.
Today, though, I want to focus on a specific question posed by the Keltner List:
"Is [this player] the very best player in [NBA] history who is not in the Hall of Fame?"
Since Artis Gilmore earned his long-overdue spot in the Naismith Memorial Basketball Hall of Fame in 2011, there hasn't been a clear answer to the question. Excluding players new to the ballot, I think there is one player who now stands above his peers as the best overlooked by the Hall of Fame: Former Seattle SuperSonics and Milwaukee Bucks center Jack Sikma.