It is decision time for Andre Villas-Boas, he has to decide whether to bring striker Fernando Torres back into the starting line-up.
It was highly publicised that Daniel Sturridge replaced the out-of-form Torres, a move that saw the youngster score at the Stadium of Light.
The Blues have a host of players missing for this tie, midfielder Ramires, is suspended after being sent off against Manchester United in last season’s exit. Didier Drogba and Michael Essien are both injured and Romelu Lukaku and Ryan Bertrand are ineligible as they were not picked in the ‘A’ list.
Villas-Boas has European success from when he won the Europa League with Porto last season, and he was a scout under Jose Mourinho when the Blues lost in the semi-finals to Liverpool.
Leverkusen will have former Blue’s hero Michael Ballack in their squad, but whilst he is unlikely to start, he will get an excellent reception.
They have a youthful squad with winger Andre Schurrle, 20, being their star player and the one to watch.
He was signed from Mainz 05,in the summer after scoring 15 goals in 34 Bundesliga games last season.
Historically German sides have struggled at the Bridge, the Blues have never lost on home soil to a Germanic opposition and Bayer have won twice in England.
There have not been any competitive matches between the two clubs, the Blues will be looking to get off to a winning start and continuing their unbeaten European home run. They last lost in the competition against Besiktas eight years ago.
By Scott Balaam
Twitter @theshed11