A 23-year-old man has had to have his jaw rebuilt after he was attacked when he caught two men trying to steal his motorbike outside his home in Clayton.
The man went outside his house on Coatbridge Street on Sunday evening after hearing a noise in his back yard.
The offenders tried to escape over a wall but the man pulled one of them back. He was punched and kicked in the jaw before the two offenders ran off.
The victim was taken to Manchester Royal Infirmary with his injuries.
The offenders were described as white and aged 18 to 20 years, police said.
One of them is 6ft (1.83m), of average build and was wearing a grey hooded tracksuit top with the hood pulled up and black Nike tracksuit bottoms with 360 written in blue on the left leg.
The other is described as 5ft 8in (1.73m) and of slim build, with a shaved head. He was wearing a black Lacoste tracksuit.