Brad Keselowski will start on the pole for ending race after topping Elliott Mimai Speedway.
Keselowski, who was the last driver to make his qualifying run in the 49-car field, turned a lap at 167.660 mph around the 1.5-mile South Florida track for his fourth pole of the season and the 12th of his Nationwide career.
Sadler earned the outside pole with a lap at 167.131 mph.
Carl Edwards qualified third, while his Roush Fenway Racing teammate and current points leader Ricky Stenhouse Jr. took the fourth spot. Stenhouse enters the race with a very comfortable 41-point lead over Sadler. If he finishes 37th or better, he will clinch the series championship, regardless of Sadler's performance.
Jeff Green, Jake Crum, T.J. Bell, Mark Green, Jennifer Jo Cobb and Johnny Chapman failed to qualify.
The 300-mile race at Homestead is scheduled to start just after at 4:30 p.m. (et).