The long jumper, 28, was taking a walk with his dogs when he discovered an injured deer.
Lifting the animal in his arms, Greg then carried the foal for two miles back to his home in Woburn Sands, Buckinghamshire in order to get help.
Tragically, when Greg then phoned the RSPCA to report the injured animal, he was told it would have to be put down - as it had broken its leg.
But dad Greg then revealed he was not happy with this outcome, and instead took it to a nearby animal hospital to have its leg set in a splint.
Staff at the Tiggywinkles animal hospital were hopeful the deer would survive the ordeal, much to Rutherford’s joy.
Greg told twitter followers that when he came across the injured foal, it was unable to move due to the broken limb.
Sadly, late on Thursday Greg announced that the deer he named affectionately as Doris had to be put to sleep due to her injuries.