The Denmark international has been with Hannover since 2009, having initially linked up with the Bundesliga outfit on loan.
He moved to Germany after 12 disappointing months on the books of Fulham.
That forgettable spell at Craven Cottage has, however, done little to curb speculation that he could soon be on his way back to the Premier League.
The likes of Newcastle United, Everton and Aston Villa have all been linked with the versatile 30-year-old, and Andreasen admits he does feel undervalued at his current employers - with the injury struggles of his past having left him stuck on a smaller salary than his talents deserve.
He told BILD: "My current deal is on small terms. This should change, of course. I need to have a better deal.
"My agent has told me he has received some enquiries for me from some clubs. I do not know the names of these clubs. I am focused on Hannover.
"I am enjoying my spell at Hannover, but I need to get treated like a healthy first team player."