A team of 19 mountain rescuers rushed to the aid of a man stuck down an embankment before he was rushed off to hospital.
Paramedics raced out to Park Bridge off Oldham Road, opposite Daisy Nook Country Park, after an emergency call shortly after 7.45pm.
North West Ambulance Service (NWAS) called out Oldham Mountain Rescue Team (OMRT) for help, whose members had been in the middle of a training session.
Eyewitnesses reported seeing several ambulances parked up at the Daisy Nook car park in Ashton-under-Lyne, near to the border with Oldham, along with OMRT.
Having been rescued from the embankment, the man was checked over by mountain rescuers and handed over to paramedics for treatment.
He was rushed to hospital by ambulance with a knee injury.
A spokesperson for OMRT said: "On Tuesday evening, as the team were partway through our regular training at base in Greenfield, we received a request from NWAS for assistance with a male who had fallen down a steep banking in Bardsley Vale, sustaining a knee injury.
"NWAS Hazardous Area Response Team (HART) were on scene providing medical treatment but our specialist skills were needed for a rope extraction up the slope.
"After carrying out our own medical assessment, the casualty was packaged on our stretcher and hauled the short distance up to the path, where the stretcher wheel was added and he was taken to the waiting NWAS ambulance.
"It was then back to base to sort the kit and finish off the medical training we'd abandoned. Nineteen OMRT personnel were involved for just over an hour and 20 minutes."
A spokesperson for NWAS added: "We responded to an incident after a person needed rescuing after slipping down a hill.
"We received a 999 call at 7.48pm.
"HART were assisted by mountain rescue, and a man was taken to hospital."
