Liverpool have reportedly drawn up a four-man shortlist of midfielders who could replace Georginio Wijnaldum at the club this summer.
Wijnaldum left Anfield when his contract expired at the end of June, going on to sign for Paris Saint-Germain on a free transfer.
Speculation over the future of captain Jordan Henderson has also contributed to Klopp wanting midfield reinforcements, and the Daily Mail reports that Liverpool have identified four players who could fit the bill.
Liverpool are also thought to be looking at AC Milan's Franck Kessie and Saul Niguez of Atletico Madrid, although they could face stiff competition for the latter's signature, with Manchester United also interested.
The Reds have only brought in one new signing so far this summer, with centre-back Ibrahima Konate joining from RB Leipzig in a £36m deal.