It happened around 10:30 a.m. in the area of Meadow Lane and W. 9th Street.
Action News has learned the officer was taken to Wilmington Hospital for treatment after suffering two head injuries.
City officials said in a statement that the officer is expected to be released from the hospital later Tuesday.
The suspect's mother told Action News that her son got into a fight with his girlfriend, and the girlfriend called the police.
The mother said the next thing she knew, she saw her son fighting with the officer on the grass. She said her son was on top of the officer, swinging his arms.
Chopper 6 over incident that left police officer injured in Chester
The suspect was later taken into custody. His name has not been released.
Officials said they are pursuing an involuntary mental health evaluation.
"We are grateful that our officer's injuries are not life-threatening and that he is expected to recover," said Mayor Stefan Roots in a statement. "The safety and well-being of our police officers remain of utmost importance."
Video from Chopper 6 showed several Chester police vehicles on the scene.
There were multiple evidence markers and what appeared to be a white jacket with blood on it that police have since taken as evidence.