This case study aims to discuss a proposal for identifying anterior cruciate ligament injury (ACL) risk by observing the variability of side cutting kinematics with respect to the development of fatigue. One participant (n=1) sustained an ACL injury while performing a side-cutting task during the latter stages of a soccer match a few months after a recorded laboratory session. Data from his laboratory session were then compared to matched samples of seventeen healthy, uninjured participants (n=17). The injured participant was found to have performed his side-cutting task with a lower deviation than mean variability before the later stages of the second half of simulated soccer match-play. Over time, the participant performed sidecutting tasks with increasing variability in sagittal plane kinematics, suggesting that compensatory actions may have been implemented to facilitate the task execution. This elevated variability may be indicative of an increased risk of ACL injury. Further prospective investigation is warranted to gain a deeper understanding of how variabilities may play a role in task execution performance with respect to injury mechanisms.