Cahill, 32, fell down the pecking order in Chelsea's defence last season, and Simon Johnson of the Evening Standard reported Cahill's told friends he wants more assurances over playing time from new manager Maurizio Sarri.
With the recent spike in reports linking Rugani with a move to Chelsea soon after Sarri was installed as manager, it seems a new era is beginning at the club. Cahill previously spoke about Antonio Conte's uncertain future as chief and took a relaxed approach to the matter, via Omnisport:
Johnson also provided quotes Cahill gave recently regarding his status at Stamford Bridge and whether he'd be around in the long term: "I don't know, to be fair. I spent six years with Chelsea, I played a fantastic World Cup and maybe it is time to change something. It is not my decision. The club will decide. Now I just want to go on holidays and we will see what happens."
Sarri arrives at Stamford Bridge with a big selection of centre-back talent, and that still hasn't prevented the Rugani reports. Antonio Rudiger, Cesar Azpilicueta, David Luiz, Andreas Christensen, Ethan Ampadu and Kurt Zouma are all set to compete alongside Cahill for similar places in the squad.
The competition will be even more cutthroat than it was under Conte, who preferred three central defenders in his system, while Sarri has historically opted for a more conventional four at the back.
According to Corriere dello Sport journalist Alfredo Pedulla, negotiations are taking place regarding the possible transfer of Rugani:
It may be Chelsea's best option to sell Cahill this summer, considering he has only one year left on his contract and isn't likely to earn an extension on his current deal as he prepares to turn 33 in December.
The veteran still managed to make 43 appearances across all competitions last term, and after seemingly falling out of favour, he helped the team when needed to remind of his quality, per the Mail On Sunday's Rob Draper:
Any decision on Cahill's future isn't likely to be immediate, with the England international on holiday after he offered cover during the Three Lions' run to fourth at the 2018 FIFA World Cup.
Despite his contributions and the benefit of helping fill Chelsea's quota of homegrown players, the Blues could face up to losing Cahill this summer unless Sarri is willing to guarantee him a better run in the starting XI.