Jan Oblak (Atletico Madrid)
Chelsea have conceded 49 goals this season - more than any other team in the top half of the Premier League and the same number as 14th-placed Crystal Palace. If they want to challenge for the title next term, they'll have to tighten up at the back.
Frank Lampard doesn't seem to trust Kepa Arrizabalaga, which is why the Blues have been linked with Oblak in recent days. The Atletico Madrid man would certainly be an upgrade on the Spaniard, with many viewing him as the best goalkeeper on the planet.
Yet that status is precisely why Chelsea will find it difficult to prise him away from Atletico. Oblak, an agile and imposing goalkeeper, has a release clause of £108.9m, which could be too much even for the free-spending west Londoners.
Andre Onana (Ajax)
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Chelsea have already signed one member of the Ajax squad that took the Champions League by storm last season, with Hakim Ziyech joining the club in a deal worth an initial £33.4m.
Onana could yet follow his former team-mate to Stamford Bridge. The Cameroonian custodian looks set to seek pastures new this summer, with Barcelona among the sides linked.
Onana would be an asset to Chelsea too. He's comfortable with the ball at his feet and can help build the play from the back, while his sharp reflexes and athleticism also stand out.
Out of contract in 2022, the 24-year-old is thought to be available for around £35m.
Nick Pope (Burnley)
Pope has arguably been the standout goalkeeper in the Premier League this term, even if his contributions sometimes go under the radar. He's kept clean sheets in 40.5% of his appearances in 2019/20, a phenomenal ratio for a player at a mid-table club.
Tipped to challenge Jordan Pickford and Dean Henderson for the England No.1 jersey at next summer's European Championship, Pope is an excellent shot-stopper who rarely makes mistakes.
Impressing under Sean Dyche at Burnley doesn't necessarily mean the 28-year-old would thrive at Chelsea, where Lampard employs a very different style of play. Compared to Kepa, though, Pope looks a more reliable prospect between the sticks.
Alex Maret (Napoli)
Gianluigi Donnarumma is better known on these shores, but the 23-year-old Meret is another young Italian goalkeeper with a bright future ahead of him.
The former Udinese man has re-emerged as Napoli's No.1 in the last few weeks, and has been a rare model of consistency in a turbulent campaign at the Stadio San Paolo.
Napoli are desperate to keep hold of Kalidou Koulibaly this summer, but they may need to sell one or two players to fund a revamp of their squad. Chelsea should test their resolve by bidding for Meret.
Dean Henderson (Sheffield United, on loan from Manchester United)
David de Gea has endured another disappointing season at Manchester United, with many supporters calling for Dean Henderson to begin next year as the club's first choice.
But despite Henderson's admirable exploits on loan at Sheffield United, Ole Gunnar Solskjaer looks set to stick with the Spaniard next season - a decision that has reportedly attracted the attention of the Chelsea hierarchy.
According to the Manchester Evening News, the Blues have held talks with Henderson's representatives and are prepared to double his wages in an attempt to prise him away from Old Trafford.
Henderson has been excellent for the Blades this term, helping Chris Wilder's side conceded the fourth-fewest number of goals after 37 games.
Mike Maignan (Lille)
A PSG youth product, Maignan earned rave reviews for his performances for Lille in 2019/20. The 6ft 3in goalkeeper is physically imposing and commands his box well, which is a notable weakness in Kepa's game.
The 25-year-old is under contract for only two more years, which means Lille would have to carefully consider any incoming offers unless he pens a new deal before the start of next season.
Tipped as a long-term successor to Hugo Lloris for the France national team, Maignan has also been linked with Tottenham, Lloris' club team, in the last few months.
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Greg Lea is a freelance football journalist who's filled in wherever FourFourTwo needs him since 2014. He became a Crystal Palace fan after watching a 1-0 loss to Port Vale in 1998, and once got on the scoresheet in a primary school game against Wilfried Zaha's Whitehorse Manor (an own goal in an 8-0 defeat).