Fulham midfielder Riise, younger brother of former Liverpool player John Arne Riise, made a brief substitute appearance in the midweek draw with Reading after joining the Blades until the end of the season.
The 27-year-old, told by Norway coach Egil Olsen he needs regular first-team football after languishing in Fulham's reserves, said: "The move here is a chance for me to play matches and show everyone my ability.
"I have to think about my international future so playing games for Sheffield United is hopefully going to secure my place in the Norway squad.
"Dropping a division doesn't concern me because I have spoken to a lot of people, including my brother (John Arne), who has played against the Blades for Liverpool and it's a really good club, with a good stadium and excellent supporters."
Source: PA
Source: PA