Voller believes Adler could decide to extend his current contract, which is set to expire in 2012.
Voller told Sport 1: “Rene Adler has been a supporter of Manchester United since he was a child and he has a buy-out clause in his current contract just in case United come up.
“This clause is in a region of beyond £17m.
“We have the ambition to keep him at our club and we are in good talks. We have the intention to see him sign on for more seasons.”
