Premier League champions Liverpool seem to have an impasse growing within their ranks. Gini Wijnaldum, with just a year left on his current contract, hasn't yet signed a new deal with the Reds.There have been rumours that the Dutchman could leave this summer, with Liverpool intending to rather lose him now for a fee, than on a free next summer.Wijnaldum is one of Liverpool boss Jurgen Klopp's most trusted lieutenants on the field. But the Dutchman will be 30 later this year. And with contract negotiations taking much longer than Liverpool might have expected, the Reds might well be considering moving on and replacing Wijnaldum.However, that will not be an easy task at all, because of the versatility that Wijnaldum provides in the middle of the park. Under Klopp, Wijnaldum has traversed the entire midfield and played various roles. He's the been the holding midfielder sometimes, the advanced #8 sometimes, and occasionally has even moved into the front three.So, if they were to lose Wijnaldum this summer, Liverpool are going to have to switch things around with respect to the roles of their other midfielders, mostly captain Jordan Henderson. Fabinho obviously has his role as an undisputed starter in the no. 6 role.Here are five players who could possibly be looked at if Liverpool were indeed interested in replacing Wijnaldum.#5 Sergej Milinkovic-Savic | LazioLazio's Sergej Milinkovic-SavicThe Serbian, who plays for Lazio, has already become one of the best and most sought-after box-to-box midfielders in all of Europe.Milinkovic-Savic operates on the right of a midfield three at Lazio, along with Lucas Leiva and Luis Alberto. He initially broke out with Lazio in 2017-18 as a no. 10. Milinkovic-Savic has demonstrated his versatility already and that makes him a viable candidate to play in a Klopp midfield, where multiple roles need to be filled.Claudio Lopez on Sergej Milinkovic-Savic:"He could have played in my Lazio, alongside Veron and Simeone in the middle." pic.twitter.com/zoiDyNNqIi— LazioLand (@Lazio_Land) June 9, 2020Liverpool do rely on their front three and their flying full-backs to create and score most of their goals. The midfielders, on the other hand, do a lot of the dirty work, covering for Trent Alexander-Arnold and Andy Robertson when they bomb forward.However, with Milinkovic-Savic, who plays predominantly on the right, could be helped by the fact that Alexander-Arnold is not the sort of full-back who will constantly run to the by-line.The young Scouser has a fabulous ability to whip crosses in from a deeper position. In that kind of set-up, Milinkovic-Savic could occupy the inside-right channel. This would allow Mo Salah to drift further in-field, further enhancing the Egyptian's goal threat.But if needed, Klopp has also used Wijnaldum in a role that allows him to get in the box freely. This was seen during last season's memorable UEFA Champions League semifinal win against Barcelona when the Dutchman scored twice. The Serbian would be ideal in that role as well.#4 Denis Zakaria | Borussia MoenchengladbachDenis Zakaria had a superb season for Bundesliga side Borussia MoenchengladbachZakaria is another player who may not directly replace Wijnaldum in the current Liverpool setup, but one that the Reds have been linked with in the recent transfer window.Zakaria has already shown that he is adaptable to different systems, playing either as a no.6 in a 4-3-3 or as one of a double pivot in a 4-2-3-1. He might not straightaway suit the no. 8 role that Wijnaldum mostly plays in the Liverpool 4-3-3. But where he would add steel is that he could be brought in as someone to deputise for Fabinho.Naby Keita ended the season on a storming note for the Reds, and might even start the next one as the first choice no. 8. But Zakaria could well be slotted in that role too, with him having the physical attributes and the tactical awareness to do so.Klopp has already shown at Liverpool that he isn't afraid to use players in positions that may not seem their most natural. And the biggest example of that is Wijnaldum himself. He arrived as a no.10, but then reined himself in to be the mostly defensive no.8 that he now is.