Born in Caerau near Maesteg in the north of the Llynfi Valley, Bateman was a precocious rugby talent playing for his Primary and Junior school team, Plasnewydd (coached by David Rogers), and the Maesteg Town team in the 1970s. He excelled at both rugby and soccer, being a very fast sprinter, and also possessing a very large lung capacity which allowed him to recover from physical exertion rapidly. He was an outstanding player for Maesteg Comprehensive School where he was coached by Peter Williams, brother of Wales and British Lions superstar J.J. Williams (also from the Llynfi Valley), and by Wales back row international Gareth Williams. He began his senior rugby career for Maesteg RFC "The Old Parish" at their Llynfi Road ground. As a centre for Neath, Bateman gained four caps for Wales in 1990 before moving to rugby league with Warrington Wolves, but returned after rugby union went professional in 1996 to gain a further 31 Wales caps and one for the British and Irish Lions 1996-2001. In rugby league he played for Wales 13 times and Great Britain twice. He also had a successful spell in Australian rugby league with the Cronulla Sharks. During his 5 year stint at Northampton Saints he was a key figure in their Heineken Cup triumph in 2000. He became known as "The Clamp" in his rugby league days because of the ferocity of his tackling. He follows in a tradition of rugby talents from the Llynfi Valley including Ray "Chico" Hopkins, J.J. Williams and Gwyn Evans.
Following his retirement from professional rugby, Bateman continued to play for his hometown club of Maesteg. Putting his education to good use, he now works in the Hematology Department of Princess of Wales Hospital but still plays at an amateur level for local club Heol-y-Cyw.