This has put clubs in League One and the second tier needing reinforcements on red alert – especially those in need of a centre-back.
Pompey arguably fall into this category with Hayden Carter looking likely to remain at Blackburn this summer, and Sean Raggett yet to extend his stay at the Blues.
But who could they sign for free in pre-season?
Here’s who we found among the names set to leave their clubs at the end of their contracts in June.
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Gary Cahill, Aden Flint, James Chester and Michael Hector Photo: The News
. Michael Hector – Fulham
The 29-year-old played a sizable part in Fulham’s promotion to the Premier League in 2019-20, but struggled to adapt as the Cottagers were relegated the following year. The centre-back made only seven appearances last season before his release, but it’s expected he will have a number of options on the table. Picture: Ben Stansall - Pool/Getty Images Photo: Pool
. James Chester – Stoke
Chester would come with bags of Premier League experience following his spells with Hull and West Brom. The 33-year-old won promotion to the top-flight with Aston Villa in 2019, but failed to do the same with Stoke during his two years at the club. Picture: Nathan Stirk/Getty Images Photo: Nathan Stirk
1. Michael Hector – Fulham
The 29-year-old played a sizable part in Fulham’s promotion to the Premier League in 2019-20, but struggled to adapt as the Cottagers were relegated the following year. The centre-back made only seven appearances last season before his release, but it’s expected he will have a number of options on the table. Picture: Ben Stansall - Pool/Getty Images Photo: Pool
2. James Chester – Stoke
Chester would come with bags of Premier League experience following his spells with Hull and West Brom. The 33-year-old won promotion to the top-flight with Aston Villa in 2019, but failed to do the same with Stoke during his two years at the club. Picture: Nathan Stirk/Getty Images Photo: Nathan Stirk
3. Gary Cahill – AFC Bournemouth
The former Champions League and Premier League winner enjoyed a singular season with AFC Bournemouth before being released after gaining promotion to the top-flight. His age at 36 may put clubs off, but still an experienced and knowledgeable option. Picture: Alex Pantling/Getty Images Photo: Alex Pantling
4. Alfie Mawson – Fulham
Following Hector out the door at Craven Cottage is the ex-Swansea defender. Signed by the club for £20 million, the 28-year-old has struggled to live up to the price tag and made only eight appearances last season. Picture: Catherine Ivill/Getty Images Photo: Catherine Ivill