I agree with this. Moneyball was aimed at finding undervalued players. It was also aimed at trying to make some of your good players appear overvalued (e.g., by letting your 3rd and 4th best relievers get saves that would normally go to your best reliever).
Exactly! It is about both roster and payroll management. When the market over values assets with specific set of skills, physical dimensions or based on outdated metrics, then participants within the market tend to overspend to collect assets with those skills or that perform well above average in those metrics. Teams were overpaying for players who looked and played a certain way. They also overpaid for wins in pitchers and for batting average and RBIs for hitters. Moneyball was about finding undervalued assets whose skill set was underappreciated or who did not perform well in the classic metrics, but actually were delivering as much value based on the new metrics (ERA+, WHIP, OBP, Slugging, OPS).
Now, even though everyone is using the same metrics, Moneyball still exists, but it has evolved. Tampa Bay is really good at the current version. It is not just about finding the players no one wants, but rather diversifying your strengths and weaknesses to create a team whose parts are greater than the sum of the parts. Rather than fixate on a single set of skills or metric, they look for players with varying skills to create a more complex lineup and pitching staff. As another example, the Yankees are one of the worst at this. Their players seem to have the same exact strengths as well as the same weaknesses. So while the Yankees were loading up with right handed players with high exit velocity and barrel percentage, but also high strikeout rates, Tampa was looking for players that gave them roster flexibility who could create greater diversity within their lineup. As such, it was easy for teams to get past the Yankees lineup, but Tampa was able to make a world series using a lineup that cost half as much as what the Yankees paid just one of their players (Stanton).
A major element to their strategy is to trade high value assets right as they become arbitration eligible for multiple high profile prospects or flawed prospects at the peak of their value. By trading them away with 3-4+ years of control, they are maximizing what they ask for in return. This helps keep their costs down, but also allows them greater flexibility to bring up and send down players who still have options. Again, the Yankees are the worst at this. They held onto Miguel Andujar too long and then just released him. They held onto Jackson Frazier too long and then just released him. They held onto Greg Bird too long and then just released him. They held onto Gary Sanchez too long and then made a horrid trade to get rid of him by picking up IKF and Josh Donaldson. They have held onto Estevan Florial and Deivy Garcia way too long and now they are well beyond their peak value but both are out of options even though neither has a full year of service in the majors. The Rays know when to move on from a top prospect or player to maximize the number of assets in their system. The Yankees do not.
