The 26-year-old Scot has finally completed his loan move from Birmingham and he will stay at the AESSEAL New York Stadium until the end of the season.
Redfearn had hoped to bring Shinnie to the club before Saturday's game at Cardiff, but it was held up as Birmingham were involved in a transfer chain.
But everyone has completed their business now, allowing Shinnie to move to South Yorkshire for the rest of the 2015-16 campaign, though he will be unavailable for the Championship clash with Blues on February 13.
Redfearn said: "Andrew is another terrific attacking option.
“He is someone who can play just off the front or just in behind the front. He is a real creative talent and he will give us more strings to our bow.
“He understands his position, he has played at this level for a while now and he has done well for Birmingham.
“I think that he is a player that, on his day, can unlock the best defences in this division. He will be a really good acquisition for us.”
