Officers were called to the A390 at Highertown at around 9.50am on Tuesday 24 August.
The incident involved a blue-coloured, single-decker bus and a man riding a dark blue pedal cycle.
As a result of the collision, the male cyclist, aged in his 70s, sustained potentially life-threatening injuries and was taken to hospital.
Officers from the Roads Policing Team are appealing for witnesses or anyone with relevant dashcam footage to come forward.
Call 101, or email [email protected], quoting log number 245 of 24 August 2021.