Roberto Firmino is Liverpool’s linchpin and Klopp will need to tweak his tactics carefully if the Brazilian is not fit enough to face Barcelona on Wednesday.
The former Hoffenheim midfielder has arguably been the most important player for Jurgen Klopp since 2015.
Mohamed Salah has been directly involved in almost 100 goals since he was signed from AS Roma last summer and yet Firmino is the player that Klopp would struggle to replace the most.
It seems bizarre to suggest that Firmino is the more important forward but he brings something to the Liverpool front three that is so hard to replicate.
It’s not just his willingness to do the mule work for Mane and Salah but the intelligent runs he makes behind defenders and the way he comes to collect the ball to simply pull centre backs out of place is so hard to teach.
Just to highlight how valuable Firmino is, the only player in the world that can play his role better than he can is Lionel Messi.
The Argentine is the quintessential false nine but Firmino has put his own spin on it, relying on hard work as much as he relies on his high football IQ and Brazilian flair.
If Firmino is missing against Barcelona, there are only a handful of options available to Klopp given the high risk nature of making changes before a Champions League semifinal.
The first option would see Xherdan Shaqiri return to the starting XI. The former Stoke City man grabbed himself a pre-assist against Huddersfield and seems to be sharp despite his lack of football recently.
The Liverpool no.23 could start on the right of the front three which would allow Klopp to move Mohamed Salah into a more central role – he has enjoyed success from playing as a centre forward before.
Alternatively, and this is the one that makes more sense in terms of balance, Mane can play as Liverpool’s striker and Divock Origi can come into the side on the left wing.
His high defensive work rate makes him the better option in a Champions League semi-final. Whatever change Klopp makes, there isn’t a single player in the squad that can replicate what Firmino does and so the game plan would need to change