So, no average values for either baseball or football are first-year only.
I have a hidden first-year only flag for baseball that I need to make an interface for, and I need to do the same work for football. I was just talking to an advisor about how filtering down to just first year + live auction prices would be more useful for new owners than seeing the overall averages. Some players are kept at very low prices, and it skews the averages badly.
So, consider this noted as a wishlist item of somewhat high priority.