Complex sentence: Dillon will run 27 Xfinity races in 2017; he will not run the Iowa races in June and July, Road America, Mid-Ohio, Kentucky in September, and Homestead.
Split into simpler sentences: Dillon will run 27 Xfinity races in 2017. He will not run the Iowa races in June and July, Road America, Mid-Ohio, Kentucky in September, and Homestead.