Crystal Palace are set to sign defender Honest Ahanor on loan from Atalanta for the rest of the season, with an agreement in place for the 18-year-old to then join Chelsea on a permanent deal.The spell with Palace will give the Italy international the chance to experience the Premier League, but with them having already signed fellow centre-back Axel Disasi on loan from Chelsea this summer, are there any issues with him moving to Selhurst Park before he goes to Stamford Bridge? And what will he offer Palace over the coming months?Simon Johnson, James Horncastle and Matt Woosnam explain this unusual transfer story.So, Chelsea have a deal for Ahanor but he won’t join them until next year?Yes, that’s right. The Athletic reported last week that Chelsea had reached an agreement with Atalanta to sign Ahanor for £40million ($54.2m). Personal terms on a long-term contract were also finalised with a player they have been tracking for some time.Ahanor is seen as one for the future, rather than somebody ready to be a first-team regular straight away. After striking that initial deal with Atalanta, Chelsea discussed what would be best to do next, given they want him to continue playing first-team football. A loan emerged as a preferred option.Chelsea have since clarified that the negotiations with Atalanta were over a pre-agreement. It means he will join up with their squad next summer. Simon JohnsonBut he’s not staying at Atalanta — he’s joining Palace on loan? Do they need him?Again, yes. Palace have a good relationship with Chelsea, and Ahanor will help bridge the gap left by Chadi Riad’s anterior cruciate ligament (ACL) knee injury that is expected to keep him out until at least late in the season.The two Premier League clubs have done transfer business in previous windows and also this summer, with centre-back Maxence Lacroix swapping south London for west London in a £52million deal in July and then Disasi going the other way on loan a few weeks later.As a left-footed centre-back, Ahanor will presumably take Riad’s place in the back three, even though he is only 18 and has fairly limited experience (35 games for Atalanta, with 18 starts; two full Italy caps this June) and minutes at senior level.Chelsea have loaned defender Disasi to Palace for the season (Sebastian Frej/Getty Images)This signing gives Palace five players to cover the three centre-back spots, but the question marks are over the overall quality of their options at the back and whether it’s enough to see them through the season.They have conceded six goals in losing their opening two league games and new manager Pierre Sage wants to play a more attacking style than predecessor Oliver Glasner, meaning they are more likely to be open at the back and therefore need to ensure their defence is capable of withstanding that.