I'm about to drop some color theory on you bro - so pull up a chair and listen up. What you perceive as color comes in two different forms - color from a light source & color as how it's reflected off a light source. The color you're seeing is entirely dependent on it's light source - cooler colors appear warm under direct sunlight compared to ambient light; warmer colors appear cooler under ambient light rather than direct sun-light. This will also change with different types of light sources often measured in kelvins otherwise known as color temperature. You're brain often interprets all of these colors depending on the lights temperature and causes you to see similar colors. When seeing colors through a camera/television - this has to be compensated for & is often achieved with setting a white balance among other things.
In this situation - you have two different materials reflecting a light source in different manors. The helmet will reflect light differently than fabric & often times the multiple light sources under a stadium settings (stadium lights - sometimes different bulbs running at different temperatures due to age combined with sun-light - which depending on the time of day can cause light from the sunlight to reflect off it's surroundings picking up tones of color from anything from the field, to the buildings & cloud lines) All of this crazy light hitting two different objects compounded with each material reflecting all this crazy light differently - basically - the helmet reflects the stadium lights better than the jersey & the jersey reflects the sun better than the helmet. If you were to properly light each the jersey & the helmet in a studio with a good light source for each - a good photographer could make them match perfectly.
Bottom line It will never match perfectly & all teams with colors containing blue, purple, green or any other cooler color that play under the sun will deal with issues where shades occasionally appear not to match.
