He made his on-field début on 17 January 1998, and in six seasons with the club played 133 games (started 130), scoring 38 tries, 85 conversions & 69 penalties for a total of 567 points.
[2] He jointly holds the club record for most conversions in a single match (10 v Waterloo on 11 March 2000) He played his last game for Rotherham on 8 May 2004 against Newcastle Falcons.
[4] He subsequently launched a case at against Coventry RFC at an employment tribunal for breach of contract and constructive unfair dismissal.
[5][6] Following his departure from this post, he signed as player-coach for local team Kenilworth R.F.C., making his début on 13 January 2007 in a 20–6 away victory against Camp Hill in Midlands Division 2 (West).
Umaga was the new head coach of Nuneaton R.F.C.,[8] losing his first match in charge, a pre-season friendly against Newbury, by a score of 22–37.