Officers attended and established three males, aged 18, 17 and 14, had been assaulted.
They were taken to hospital and are expected to make a full recovery.
An investigation is underway.
DS Roger Jones, of GMP’s Salford district, said: “Thankfully the victims weren’t seriously injured. Nevertheless, enquiries are ongoing to identify the person responsible.
“We know that there were a number of people in the park at the time so I would appeal to them to contact us or Crimestoppers, anonymously.
“I would also encourage anyone else with information which may assist us with our enquiries to do the same.”
Anyone with information should contact police on 0161 856 2079 quoting 1474 28/12/20 or the independent charity – Crimestoppers, anonymously, on 0800 555 111.