We'll keep track of changes in his ROY odds in this file.
All odds courtesy of Caesars Sportsbook.
Rookie of the Year odds
Caesars posted ROY odds on June 18, two days before the 2019 NBA draft. As the projected No. 1 pick, Williamson opened as the prohibitive odds-on favorite, at -450. "Zion is a giant favorite, but I don't know if it's big enough. It's one of those things if I take a max bet, then I might go [much higher]," Caesars head of risk Jeff Davis told ESPN at the time. Memphis Grizzlies guard Ja Morant and New York Knicks guard RJ Barrett had the next-best odds, at +450. The three represented the top three picks in the NBA draft.
In his fourth preseason game, Williamson apparently injured his knee, and several days later, it was announced that he would miss the start of the 2019-20 season because of a knee injury. Morant became the betting favorite on Oct. 29, with Williamson falling to the third-best odds.
Odds (Oct. 29):
Odds (Jan. 22):
After Williamson's exhilarating debut, Caesars shortened his odds to 8-1 (tied with Nunn), with Morant still the favorite at 1-7. According to ESPN Stats & Information data, no player has won the award after playing fewer than 50 games. The maximum number of games Williamson can play this regular season is 38.
Odds (Jan. 23):
Zion Williamson cut into Ja Morant's odds after Williamson and the Pelicans beat the Grizzlies 139-111. Williamson had 24 points in that win, and Morant had 16. The Pelicans outscored the Grizzlies by 25 points when Williamson was on the court. He became the second rookie in NBA history to score at least 10 points and shoot above 50% in each of his first five games, according to the Elias Sports Bureau (Cedrick Hordges was the first).
Odds (Feb. 1)
After another brilliant game, in which he scored 21 points on 9-for-11 shooting against the Bulls, Williamson moved to +250. The performance moved his field goal percentage to 57.4%, the best through eight games by any rookie since Hakeem Olajuwon in 1984-85.
Odds (Feb. 7)
Williamson sat out the previous night against the Pacers, but he still cut into Morant's odds, moving to 2-to-1, his shortest odds since the start of the season.
Odds (Feb. 9)
One day later, it was Morant's turn to have a big game, with 27 points, 10 rebounds and 10 assists, his first career triple-double. He became the first rookie this season with a triple-double and the second Grizzlies rookie to record one, joining Shareef Abdur-Rahim in 1997. That moved Morant back up to a -650 favorite. These odds held through the All-Star Break, despite Williamson's back-to-back 30-point games in his final two outings before the break.
Odds (Feb. 10)
After his fourth consecutive 25-point game, this time against the Warriors, Williamson moved back to +250 to win Rookie of the Year. Morant dropped to -350 after the Grizzlies lost back-to-back games to kick off the second half of their season.