This study aimed to determine if abdominal muscle thickness, activation and symmetry are associated with prospective in-season injury among adolescent cricket pace bowlers.A quantitative, prospective, observational study design was used.Data was collected at an indoor venue at a secondary school.28 injury-free, male, adolescent pace bowlers between the ages of 13 and 18 participated.Muscle thickness of the transversus abdominis (TA), internal oblique (IO) and external oblique (EO) muscles were measured at rest and during an abdominal drawing-in maneuver (ADIM) i.e. activation, using ultrasound imaging. Incidence of injury was monitored monthly during the cricket season.Thickness of the non-dominant IO at rest was greater than the dominant side for pace bowlers who remained injury free during the cricket season (p = 0.01, effect size (ES) = 0.65). This was, however not the case for bowlers who sustained injuries (p = 0.47; ES = 0.24). TA percentage change during ADIM (activation) on the dominant side was less in bowlers who sustained non-contact injuries compared to those who remained injury free (p = 0.03; ES = 1.17).Asymmetry in IO thickness may play a protective role against injury, whilst poor TA activation on the dominant side may pose a risk to injury.