A sum of around 30 million euros (Â£22.5million) is reported to have been agreed for the transfer, which Schurrle's agent Ingo Haspel told Germany's SID agency "should go through on Friday."
"There are still a few things to discuss, but we're no longer talking about figures," Haspel added.
Until those have been resolved, Wolfsburg are holding back on confirming the transfer, focusing instead on Friday night's Bundesliga clash with Bayern Munich.
"The fact is, all of the required signatures are still lacking," Wolfsburg director of sport Klaus Allofs told ARD television.
"No contract has been signed and I'm a bit old-fashioned and there are still some obstacles to get round
The ink is not yet dry."
The 24-year-old nevertheless looks certain to return to Germany, where he played for both Mainz and Bayer Leverkusen before joining the Blues in 2013.
He would become the most expensive player in Wolfsburg's history, eclipsing the 22 million euros (Â£16.5million) they paid Chelsea for Kevin De Bruyne in the summer.
Source : PA