On October 11, at approximately 21:00 BST, the adolescent was hurt while being arrested in Kingstanding, Birmingham.
Police said armed cops and a dog handler were responding to a report from a guy who said he was being chased by a gang with machetes.
The incident has been reported to the Independent Office for the Conduct of Police (IOPC).
The officers were summoned to Finchley Road at 20:20, and the dog was deployed after the gang fled.
“An ambulance was soon called,” the source, noted, “but officers took him to the hospital also to ensure he received timely medical attention.”
According to West Midlands Police, a combat knife was discovered at the scene.
The 14-year-old, who was detained on suspicion of a public order offense, is still being held on bail as investigations continue.
A spokeswoman for the IOPC confirmed that the organization had received a report from West Midlands Police about the boy’s alleged injuries from the event.
“We will undertake a review to see what additional action we may need to take,” said the spokesperson.