Thames Valley Police is appealing for witnesses following an assault in Charvil.
Between 8.30am and 9.30am on Saturday 29 June, the victim, a man in his forties, was walking with his dog and a group of people through a field to the rear of Charvil Community Tennis Club, Park Lane.
A man, also with a dog, approached and the two dogs began fighting.
The victim and the man were then involved in an altercation.
One of the group that the victim was walking with managed to restrain the offender and calm him down. The offender then walked off and got into a black car.
The victim received injuries that required medical treatment.
The offender is described as a white man, aged in his forties, around 6ft 3ins tall and of large build. He had short, brown hair with short facial hair. He was wearing a light blue running t-shirt, dark coloured, running shorts and dark coloured trainers.
Investigating officer, PC Andy Clark, based at Loddon Valley police station, said: “I am appealing for anyone who may have witnessed this incident or who may have any information to please come forward.
“I believe the offender got into a large black car that was similar to a people carrier and may have been a Vauxhall Zafira.
“Anyone with information can contact police on the non-emergency number 101, quoting reference ‘43190196991’ or make a report online.
“Alternatively, you can contact the independent charity Crimestoppers anonymously on 0800 555 111.”