Fabregas, who spent five years at Stamford Bridge after joining Chelsea from Barcelona in 2014, has given a transfer recommendation to Blues boss Graham Potter and club owner Todd Boehly.
Chelsea spent more than £250m on new signings last summer but are expected to splash the cash again next month after a slight wobble under Potter.
The former Brighton boss made an encouraging start to his tenure in west London after replacing Champions League-winning manager Thomas Tuchel, but Chelsea lost three Premier League games in a row before the World Cup to slip to eighth in the table.
With the transfer window set to re-open in January, Chelsea have been linked with moves for the likes of Josko Gvardiol, Jude Bellingham and Andrey Santos.
Fabregas has named another player Chelsea should target, insisting that RB Leipzig and Spain star Olmo would be a ‘great addition’ to Potter’s squad at Stamford Bridge.
Olmo, 24, has emerged as one of Leipzig’s most important players over the past three seasons and played in all four of Spain’s games at the Qatar World Cup.
Asked in a Twitter Q&A to name the Spain player he would like Chelsea to sign, Fabregas said: ‘Dani Olmo could be a great addition if Chelsea continues to play in this system.’
Fabregas also revealed he was ‘really upset’ after Chelsea’s Champions League last-16 defeat to Paris Saint-Germain in 2014-15.
Jose Mourinho’s side were expected to prove too strong for PSG but drew 3-3 over the two legs, with the French giants going through on away goals.
Asked which game he looks back on with regret, Fabregas added: ‘Chelsea vs PSG in the Champions League. We took it for granted and paid for it. I was really upset with myself.’
Fabregas, meanwhile, delivered his verdict on former Chelsea academy star Jamal Musiala, who has become a key player for Bayern Munich and impressed at the Qatar World Cup despite Germany’s early exit.
He said: ‘I really like him. Top talent, intelligent and it looks like he has great determination.’
For more stories like this, check our sport page.