The 23-year old Dane is set to sit behind the Royals top two keepers in Adam Federici and Alex McCarthy and Appleton sees that as a good opportunity to offer him another loan deal following short-term spells with Torquay United, Rushden & Diamonds, Brentford, Brighton & Hove Albion and Bristol Rovers over the past four years.
"Mikkel is one we enquired about," Appleton said. "I was not sure what response we would get from Reading and his agent as to whether he would want to come to League One or go in to the Championship.
"But the response we got straight away from the boy himself and the agent was really positive.
"The boy from day one spoke really highly about the football club which was a breath of fresh air. Everybody else at the minute seems to stick the boot in.
"That helps me that here is a player desperate to come in to the football club.
"Everything has been agreed for a season-long loan."