For high quality knee MRI image acquisition, the coil must be centrally aligned with the knee. However, precise alignment can suffer from patient motion and is currently performed by eye. We propose a method to automatically measure the misalignment between coil and knee to alert the clinical operator. This is done by calculating the distance between the coil and the knee joint gap by processing the localizer image with a machine learning technique, which was achieved with a mean accuracy of 3.3 mm. Our experiments further indicated a safe margin for knee-to-coil misalignment within a threshold of 20 mm.