Born in Edmonton, London, Riza started his career as a youth with Arsenal and made his first team debut on 2 November 1998 against Derby County in the League Cup. He also travelled with the team on away fixtures against Dynamo Kyiv and Panathinaikos as a substitute in the Champions League. With few first-team opportunities at Arsenal, during 1998-99 he went on loan to ADO Den Haag for three months, scoring five goals for the Dutch side.

In the 1999-2000 season, he moved to West Ham , but was unable to break into the first team. He went on loan to Barnet and Cambridge United, and signed a permanent deal with the latter in 2002. During the 2002-03 season he scored 17 goals for United, which prompted a move to Turkish Super League side Denizlispor. He scored 10 goals in 39 games and in January 2006, he signed for Trabzonspor. Things didn't go too well for Omer at Trabzonspor and he left, citing a lack of wages as his reason. Trabzonspor held on to his registration and he was unable to play for any other club.

Last season Riza came to us on trial and made his debut as a second half substitute against Rotherham, thanks to the decision by a Swiss judge the previous day.

Omer has since signed a 1 year deal with us and is aiming for a place alongside Grant Holt up front..