The sporting director has again spoken out regarding the youngster's reported future move to Stamford Bridge, warning the Blues that any deal must satisfy the Bundesliga outfit.
Speculation has been rife that the 22-year-old is set to join the west London club in the summer, with reports in Germany suggesting he has already agreed personal terms on a move to Stamford Bridge.
Voller revealed last week he was in London "to negotiate" a summer switch for Schurrle, with the midfielder expected to sign a five-year contract at Stamford Bridge while Kevin De Bruyne heads in the opposite direction on loan - though Leverkusen is thought to be eying a permanent switch.
"The transfer of Schurrle is a question of the total package. There are some more items and De Bruyne is one of them," Voller said on TV show Sky90.
"[De Bruyne is] a top alternative and can play a similar position like Andre. If a good player leaves we've got to sign another good, or even better, player."
Despite Chelsea reportedly being close to sealing a deal for Schurrle, Voller feels the youngster would be better served with more regular first-team football as he looks to break into the Germany squad ahead of World Cup 2014.
"Next year is the World Cup and then he wants to be a starter for Germany," Voller added. "He has the potential."