1. Leon Goretzka (Schalke)
Statistically speaking, Goretzka comes closest to matching Keita's impressive numbers, particularly in the defensive phase of the game. Both players made 2.6 interceptions and 0.9 clearances per match last season, although the RB Leipzig star averaged more tackles than his Schalke counterpart (2.6 vs 2.2).
The 22-year-old German contributes going forward, too: he scored five goals and provided three assists last term. He was perhaps a little unfortunate not to record more of the latter, with his average of 1.1 key pass per match only slightly worse than Keita's 1.3, which translated to seven assists.
At 6ft 2in and unlike the Guinean, Goretzka is a dominant figure in the air and is also renowned for the excellent timing of his runs. The youngster was linked with Bayern Munich and Arsenal during last month's Confederations Cup, in which he netted three goals. He's only got a year left on his contract and will be hot property soon enough, so Liverpool should watch his situation carefully.
2. Jean Michael Seri (Nice)
Seri was one of the main reasons why Nice were able to compete for the Ligue 1 crown last season. The 26-year-old was the conductor of his team, scoring seven goals, providing nine assists and pulling the strings in midfield.
The Ivorian is a versatile, well-rounded midfielder who's very difficult to dispossess. His brilliant off-the-ball movement means he's always an option for his team-mates, and is proactive in possession despite a 90% pass-completion rate which suggests conservatism. Seri might not be able to match Keita’s defensive contributions, but he certainly outshines him in terms of creativity: the Nice maestro’s vision is better, and his 2.2 key passes per game surpass Keita’s 1.3.
Arsenal and Tottenham have both been mentioned as potential suitors, but it appears that Roma have come closest to signing him this summer. The Serie A side haven't yet met Nice's €40m demands, however, which could open the door for Klopp and Liverpool.
3. Mateo Kovacic (Real Madrid)
Kovacic is another player who has been heavily linked with a move to Anfield before. For the majority of teams across the continent, the Croatia international would be an automatic starter; Real Madrid, though, are not like most teams on the continent, and Kovacic has struggled to break into the starting XI since joining from Inter in 2015. With the arrival of Marcos Llorente and Dani Ceballos this summer, there's a strong possibility that he will find it even more difficult to make his mark at the Bernabeu next season.
It’s difficult to determine the Croat’s best position in midfield, as he can perform admirably in a number of roles thanks to his energy, dribbling skills, tactical intelligence and wide range of passing. Signing Kovacic would provide a huge boost to several top teams, and Liverpool are one of them.
4. Piotr Zielinski (Napoli)
Liverpool had the chance to sign Zielinski last summer, but the Pole opted to join Napoli instead. With Maurizio Sarri regularly rotating his midfield, Zielinski gradually became more important as his team challenged for the Serie A title.
A return of six goals and seven assists in all competitions was highly respectable, but the 23-year-old's best work came elsewhere. He's certainly polished plenty of his skills since arriving at the Stadio San Paolo: Zielinski is particularly brilliant in transition and terrific at carrying the ball forward from his own half.
A quick-thinking midfielder with an endless supply of fuel, Zielinski suits Klopp’s preferred player profile, which could lead to the Reds reviving their interest in him. This time they'll need a lot more cash to lure him to Anfield than they intended to use 12 months ago.
5. Sergej Milinkovic-Savic (Lazio)
Liverpool have supposedly already attempted to buy Milinkovic-Savic from Lazio, but they were quickly rebuffed by the Serie A side. Every player has his price, though, and an increased bid could be enough to persuade the Biancocelesti to reconsider their stance.
Milinkovic-Savic is a very different player to Keita, but his qualities could be just what Liverpool need to strengthen their midfield. With seven goals and nine assists to his name, the 22-year-old enjoyed a stellar campaign in 2016/17, when he established himself as one of the best young players in Italy. A hard-working midfielder who can dictate the tempo of a game, Milinkovic-Savic would likely become a focal point at Anfield.
He's got intimidating physique, too, which complements his array of technical skills - the Spain-born Serbia U21 international can easily hold on to possession and orchestrate attacking moves. With plenty of room to grow, Milinkovic-Savic looks ready to take the next step in his career.
6. Renato Sanches (Bayern Munich)
UEFA’s 2016 Golden Boy winner endured an underwhelming debut season at Bayern Munich. The Portuguese youngster dazzled at Euro 2016 in France and made a significant contribution to Portugal's triumph, but life at the Allianz Arena proved much tougher.
The 19-year-old only started six times for the Bundesliga champions, and Bayern are willing to let him go this summer – albeit only on loan for now, unless an irresistible offer comes their way. Big-spending Milan are interested but couldn't lodge a big enough offer a player who was heralded as one of Europe's outstanding young stars during his time at Benfica. They're still favourites to get him on loan for a year, however.
But might Liverpool fancy themselves as better suitors? With Klopp's impressive record of helping to launch the careers of gifted prodigies, Anfield could be the perfect place for the Portuguese to continue his development.
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