Every transfer has a knock-on effect, with one departure usually leading to an arrival.
Chelsea's capture of Kalidou Koulibaly is no different. The 31-year-old defender leaving for the Blues has left a hole in the Serie A side's defence and one they need to fill.
Elsewhere, highly-rated defender Milan Skriniar could be set for a Barcelona switch after Paris Saint-Germain baulked at Inter Milan's asking price. La Liga giants are keen on the Slovakian after losing the race for Jules Kounde.
And former Bayern Munich midfielder Renato Sanches is still seeking a way out of Lille after finding his feet again. PSG have yet again turned their noses up on another transfer and so AC Milan are hoping to capitalise.
Here's the latest football rumours from around Europe.
Napoli find Koulibaly replacement
Napoli have wasted no time in replenishing their defence after the £33 million defection of linchpin Kalidou Koulibaly to Chelsea.
According to reports in Italy, the Serie A club are ready to trigger Fenerbahce's £18m release clause for South Korean international defender Kim Min-Jae.
The player is understood to have agreed terms on a three-year contract worth £2.2 million a year – and Napoli's trolley dash may not finish in Turkey.
They are on the trail of Hallas Verona's Argentine striker Giovanni Simeone, 27 – the son of Atletico Madrid coach Diego Simeone.
Skriniar's future with Inter in the balance
For most of the summer, Skriniar was expected to join Paris Saint-Germain, but even the super-rich French champions baulked at Inter's £63 million asking price.
Now, according to Italian broadcaster Sport Mediaset, Barca are lining up an offer in case they lose out to Chelsea in the tug-of-war for Sevilla centre-half Jules Kounde.
Meanwhile, Inter's fellow San Siro tenants AC Milan want Eintracht Frankfurt defender Evan Ndicka, 22.
The Europa League winners want at least £18 million for the French under-21 international, who has only 12 months left on his contract, and Germany's biggest-selling paper, Bild, say Ndicka may be prepared to run his contract down to force a move.
Restless Renato
Former Bayern Munich midfielder Renato Sanches, who spent an undistinguished season on loan at Swansea five years ago, could be on the move.
Reports in the Italian media suggest the 24-year-old Lille star, heavily linked with Paris Saint-Germain, is growing restless at PSG's failure to turn their interest into a concrete offer.
And AC Milan are ready to step in with firm bid for the Portuguese international, who is rated at £25 million-plus by Transfermarkt, to test the Ligue Un champions' resolve.
