Twenty horses will take their posts at Churchill Downs on Saturday evening. And roughly two minutes after the start of the 145th Kentucky Derby, one of them will be the winner.

This is one of the most wide-open Derby fields in recent memory, especially after early betting favorite Omaha Beach was scratched on Wednesday because of a respiratory issue, per the race's Twitter account.

Some horses have better chances of winning the Run for the Roses than others. Here's a look at this year's field and odds, as well as some favorites and sleepers to keep an eye on Saturday.

Kentucky Derby Post Positions, Odds

1. War of Will (15-1)

2. Tax (20-1)

3. By My Standards (15-1)

4. Gray Magician (50-1)

5. Improbable (5-1)

6. Vekoma (15-1)

7. Maximum Security (8-1)

8. Tacitus (8-1)

9. Plus Que Parfait (30-1)

10. Cutting Humor (30-1)

11. Haikal (30-1)

12. Code of Honor (12-1)

13. Win Win Win (12-1)

14. Master Fencer (50-1)

15. Game Winner (9-2)

16. Roadster (5-1)

17. Long Range Toddy (30-1)

18. Spinoff (30-1)

19. Country House (30-1)

20. Bodexpress (30-1)

All horses that drew posts Nos. 13-20 moved in one following Omaha Beach's scratching, per the Derby's Twitter account. Bodexpress took No. 20. Odds via SportsLine, as of Thursday at 6 a.m. ET.

Favorites

The three horses with the top odds—Game Winner, Improbable and Roadster—are all trained by Bob Baffert, who has five career Kentucky Derby wins, including two in the past four years with Triple Crown winners American Pharoah (2015) and Justify (2018).

At least one of Baffert's three horses should be contending for the win in the final stretch of Saturday's race.

"It's amazing what a good horse does for your soul," Baffert said, according to the Pittsburgh Post-Gazette's Eric Crawford. "It puts some pep in your step. When you have a horse that has a chance to win the Derby, it's a totally different feeling. You can't wait to get up. It really keeps you going. It's the beauty of this race."

With Omaha Beach out of the race, the chances of one of the three Baffert-trained horses winning the Kentucky Derby went up.

Maximum Security and Tacitus are also horses with good odds that could be strong contenders to compete for the win.

Sleepers

While the Kentucky Derby winner has been the favorite for the past six years, there could also be a long shot that surprises and wins the race. In 2005, when Giacomo, a 50-1 underdog, secured the Derby victory.

No horse with odds that low should contend in this year's race, but there are some sleepers to watch heading into Saturday.

Win Win Win has finished in the money (top three) in each of its six career races. Another sleeper is Code of Honor, which is trained by Shug McGaughey, whose last horse to compete in the Kentucky Derby was the 2013 winner, Orb.

War of Will was among Kentucky Derby contenders before it suffered a patella injury during the Louisiana Derby, in which it finished ninth. Although he had an unfavorable draw and is starting from the No. 1 post, there's a slight chance War of Will could have a strong showing in the Kentucky Derby.