The former Liverpool ace has been out of action since the clash with Palermo on January 28 with a damage to a ligament in his left knee.
“Things are going well and I believe I’ll return earlier than first thought,” Riise told Norwegian journalists yesterday.
“I feel no pain in my knee and I’m confident I will be at the coach’s disposal in 15 days.”
It was expected that Riise would be out of action for up to six weeks.