PSCO Barbara Gornall visited the youngster's city home earlier today, as he continues to recover at the specialist Alder Hey Children's Hospital in Merseyside, her colleague PSCO Stephen Connolly said.
The accident initially saw him taken to Royal Preston Hospital as the road was closed for investigation work.
PSCO Gornall has worked her Avenham and Frenchwood beat for around a decade and has known the child since he was a baby, PCSO Connolly said.
"She is a very caring individual and cares a lot about her area and the residents in it," he added.
The card and balloon was also described by Preston Police on Twitter as a 'random act of kindness'.