Appellant got into a physical struggle with probation officers when they attempted to arrest him for a probation violation. During the struggle, he kicked a large ashtray, which fell and struck an officer in the shin. The officer sustained a cut and some bruising. Appellant was convicted of battery with injury on a probation officer in violation of Penal Code section 243, subdivision (c)(1). On appeal, he contended that the evidence was insufficient to show that he had the requisite mental state for battery, and that the trial court erred when it failed to instruct sua sponte on the lesser included offense of battery without injury on a probation officer in violation of section 243, subdivision (b). The appellate court agreed that the court prejudicially erred when it failed to instruct on the lesser included offense and reversed the conviction. A reasonable jury could have concluded that the officer’s injury did not require professional treatment and was therefore not an “injury” as defined by the statute. The trial court’s failure to instruct on the lesser included offense of battery without injury was prejudicial because it was likely the jury would have returned a guilty verdict to the lesser offense if given the option.