How do you improve a team that won the most competitive top-flight league in the world (supposedly) by 18 points?
More specifically, how do you improve a defence the conceded just 33 goals all season - over a third of which came when most of the players were suffering from a post-Premier League title hangover?
These are two questions that champions Liverpool will be seeking to answer in the upcoming transfer window and according to reports they are going to have to exercise significant financial restraint while doing so.
This is where Ozan Kabak could come in, the rare bright spark in David Wagner's chaotic Schalke defence. 90min understands that Liverpool have already made contact with the cash-strapped Bundesliga side ahead of a potential summer move and despite the Turkey international having four years left to run on his current deal, he should be available for a modest fee.
So, he fits the bill in terms of transfer outlay but would the 20-year-old actually be a good addition to Jurgen Klopp's squad?
To answer this, we first need to identity what it is that Liverpool are looking for.
In terms of playing time, Kabak would not be expected to immediately break into the first team. Barring any injury issues, Virgil van Dijk and Joe Gomez will remain unmoved as the Reds' first-choice centre-back pairing next season, while Joel Matip could also be ahead of him in the pecking order. Incidentally, the German-born ex-Cameroon international, who also arrived from Schalke, could be a good mentor for the young defender to help him settle on Merseyside.
In terms of squad role then, Liverpool are looking for a younger player to fill the void left by the departure of self-professed 'best defender in the world' Dejan Lovren to Zenit St Petersburg, while eventually challenging to be Van Dijk's regular partner.
Even though he is unlikely to be thrown in at the deep end - most Klopp signings have had slow and steady bedding in periods - a potential new recruit like Kabak will still need to be well versed in the Premier League champions' playing style if called upon. A quick glance at his passing range, suggests that some work might be required to get Kabak up to the standard of his new teammates.
While Liverpool are known for the speed and verticality of their passing, they also use short passing between their centre-backs to reset shape and rest in possession. This is evidenced by the 85.8 and 71.0 passes averaged per game by Van Dijk and Gomez respectively last season. Kabak in contrast averaged just 39.8 - albeit in a much more direct Wagner side.
The raking cross-field passes that have become a trademark of Liverpool's game could also prove challenging for the young Turkish defender. Gomez and Van Dijk both averaged close to a 90% completion rate on passes over 25 yards last season, far higher than the 75% figure posted by Kabak.
Even accounting for differences in playing style and the Reds enjoying more control of games than mid table Schlake, the disparity in these figures suggests that the Turkish defender would require a period of adjustment at Anfield.
The centre-back role isn't all about passing however, defensive attributes are also important - even for a side as dominant as Liverpool. This is where Kabak thrives. The youngster has earned himself a fearsome reputation - and a top five video on the Bundesliga's Youtube channel - through his crunching tackles over the past two seasons.
In significantly less games, Kabak registered more tackles than the Van Dijk and Gomez last season and he is also a powerful aerial presence. Schalke's midfield has frequently been bypassed like a hot knife through butter this season and it has often fallen upon the former Stuttgart man to bail his side out with a match saving block, clearance or tackle.
Additionally, his impressive pace means he's quick on the half turn. This would suit him well to mopping up when the opposition attempts to play over Liverpool's infamous high press - a tactic which has seen their Premier League title rivals Manchester City caught out on several occasions recently
In summary then, Kabak excels in most of the bread and butter areas required for a defender and is also physically imperious.
In other respects, some coaching would be required but improving raw players signed from dysfunctional sides has prove to be a Klopp-ian speciality in recent years.
Left-back Andy Robertson was plucked from relegated Hull City, Xherdan Shaqiri from Stoke City while Alex Oxlade-Chamberlain was recruited from the most dysfunctional club of all, Arsenal. Joke!
It seems then that Kabak could fit the bill of what Liverpool want in their defenders. He's young, affordable and has more than enough about him to blossom into a top class centre-back under the right tutelage.