The week leading into the 10th round of the 2021 Lucas Oil Pro Motocross Championship has been one filled with attrition as a slew of 450 Class riders will be sidelined for the Guaranteed Rate Ironman National, for various reasons.

The week began with the news that Troy Lee Designs/Red Bull/GASGAS Factory Racing's Justin Barcia would continued his recovery from a practice crash. As the days wore on, additional riders joined the list, including Monster Energy/Star/Yamaha Racing's Christian Craig, who is banged up from a big crash at Budds Creek, and Rockstar Energy Husqvarna Factory Racing's Dean Wilson, who continues to battle the Epstein-Barr virus. 

Additionally, COVID-19 infections forced both Twisted Tea/H.E.P. Motorsports/Suzuki Racing's Max Anstie and Red Bull KTM Factory Racing's Marvin Musquin to the sidelines as they recover from the virus. Musquin's positive test came on the eve of the race and was confirmed by team manager Rodger DeCoster.