Doug Domnarski is in his first season with the ThunderBolts and fifth as a pro in 2021. He was acquired in a trade with the New York Boulders on December 15, 2020. Doug's career began in 2017, when he was selected in the 27th round of the Amateur Draft by the Miami Marlins. Over the next year, he pitched in 16 games across two levels in the Marlins system and compiled a 1.40 ERA. He also spent parts of two seasons in the Detroit Tigers organization and went 1-0 with a 2.64 ERA.

Doug is a graduate of the University of Connecticut, where he pitched for two years, going 2-4 with a 5.74 ERA in 41 games (two starts). He also played two years at UConn Avery Point, posting a 17-2 combined record, and was named an NJCAA First-Team All-Ameriacn as a sophomore. He attended Stonington High School in Pawcatuck, Connecticut.