However, Cahill has rubbished the speculation and backed his manager to prove himself worthy of the post as he did during his caretaker spell in charge last season.
"From last year, when he took the job, he did tremendously well and achieved such a lot in a short space of time.
"We started the campaign really well. We're all behind him and he's definitely the right man. He proved it last year and I'm sure he will prove it this year as well."
The Blues face a Champions League trip to Juventus on Tuesday with only victory enough to ensure that their European fate is in their own hands going into the final round of group-stage fixtures.