Hein Robb enters his first year with the ThunderBolts and fifth as a pro in 2014. He signed on August 5, 2014. Hein pitched for four years in the Minnesota Twins organization. He signed with Minnesota as a 16-year-old out of South Africa. In his career with the Twins, he pitched a total of 47 games (33 starts) and posted a 6-11 record with a 4.12 ERA. He struck out 132 and walked only 60 in his 162 career innings with the Twins. Hein peaked in 2013 at class A Cedar Rapids, starting three games there and finished ninth in the Appalachian League in ERA with Elizabethton that same year.