According to German journalist Raphael Honigstein of The Athletic, the delay in finalising the deal is down to medical practicalities.
Werner can’t fly to London for his medical due to the Bundesliga COVID-19 regulations and Chelsea can’t send doctors to Germany as they would have go into a 14-day isolation upon returning.
Honigstein adds that Chelsea could use the German FA doctor, but will likely wait until the season ends in June.
Initial reports claimed Chelsea were paying Werner’s release clause of around €60m.
However, the Kicker newspaper has gone on to report that the fee will in fact be €50m, a potential bargain.