The Blues had explored a move for Granit Xhaka as part of their plans under new head coach Xabi Alonso, but the deal has failed to materialise.
Chelsea were unwilling to meet the financial demands required to sign the experienced midfielder, while Sunderland remained determined not to part with the player.
At the same time, Enzo Fernandez's potential move to Real Madrid has also cooled, leaving Chelsea facing an increasingly complex situation.
Although Chelsea were never actively looking to sell the Argentina international, the club were aware that Fernandez had been keen on a move to the Spanish giants if the opportunity arose.
We understand that Chelsea maintained throughout informal contacts that any deal would require a fee exceeding the £106 million they paid to sign Fernandez in 2023.
That valuation, which was over £115 million, ultimately proved to be a major stumbling block, with Real Madrid's unable to negotiate a deal that would meet Chelsea's expectations.
As a result, the Spanish club have claimed they were not interested in pursuing the player this summer.
The collapse of both transfers leaves Chelsea with important decisions to make as they continue shaping their squad for the upcoming campaign.
Missing out on Xhaka means the Blues must now identify alternative midfield targets, while they also need greater clarity over Fernandez's long-term future at Stamford Bridge.
There remains concern within the club that the midfielder could still seek a move away if the right opportunity arises, and Chelsea are keen to establish exactly where he sees his future before the transfer window progresses further.