The basic concept of asset valuation in sports is that you exploit other teams’ ideas about player value that differ from your own. The assumption is, of course, that your ideas are better, more based in your extensive data science intelligence gathering, and you are beating the competition with your giant brain in every deal you make.
The basics are: you acquire players that the seller undervalues, but your analysis says are good, and you dispose of players in the opposite way. But there is more to it than just buying and selling.
The management part comes in making sure the players you have that you might want to sell will bring you the best return.