The South African seamer joined Yorkshire at the start of the 2005 season under the Kolpak ruling and helped secure promotion in the County Championship in his first year.
Kruis settled in quickly at Headingley and ended the campaign as the leading wicket-taker in Division Two with 64 at 30.64 runs apiece, which included four five-wicket hauls.
He was an ever present in the championship team and also proved his ability as a lower-order batsman with several useful knocks.
His performances were rewarded when he was named Yorkshire’s Player of the Year.
He was offered a new contract at the end of the 2005 season and played for two more years, getting a further extension at the end of the 2007 summer.
That season he was plagued by injury, but still picked up eight wickets in six county championship matches and topped the county's bowling averages in the Friends Provident Trophy.
He had another successful summer in 2008, claiming five wickets and scoring a half-century in the championship match against Surrey.
He also picked up three vital wickets in a NatWest Pro40 game against Northamptonshire to secure Yorkshire's promotion into Division One.
He delayed his decision on signing a new contract at the end of the season, and was initially released, before Yorkshire chose to make a u-turn and offer him a one-year deal for 2009.