Riise joined the Giallorossi from Liverpool this summer, but has so far failed to impress.
“I just need time – give me a few months,” Riise told Dagbladet.
“I didn’t have the best of starts but we have picked up some positive results at home.
“However, I am still optimistic because it is early in the season and we will see what happens come June.
“As I said when I moved here in the summer, I will need a few months to adapt to a new type of football and a new system.
“I’m well aware that I have to improve and that the best thing to do is to play through the problems.”