Crabtree signed for Huddersfield on his 17th birthday and he made his début for the club in 2001. The following season he scored 25 tries in 37 league and cup appearances whilst playing at  during Huddersfield's National League promotion season. His breakthrough year in Super League was 2004 where, under coach Jon Sharp, he established himself as a regular in Huddersfield's first team and developed a reputation as an imposing figure with his mix of size and athleticism.
Crabtree signed for Huddersfield at age 17 and made his debut in 2001. The following season he scored 25 tries in 37 league and cup games while playing for the team during their National League promotion campaign. His breakthrough year in Super League was 2004, where under coach Jon Sharp, he solidified himself as a regular player on Huddersfield's first team and earned a reputation as an intimidating presence due to his combination of size and athleticism.