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."