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 firstname.lastname@example.org, quoting log number 245 of 24 August 2021.