With there no money to spend at Fratton Park, Pompey have looked to make the most of the loan market this season.
Andersen told bold.dk: "We had to say goodbye to a striker from Bournemouth (Wes Thomas) who had to return after a month-long spell.
"We got Scott Allan in from West Brom, which means that we have had to change our style again.
"We have had to rebuild for the third time this season, but I am optimistic. The season is long and anything can happen. It would be amazing to secure a play-off spot."