I'll throw in my two cents. We can all argue the metrics of various players, both newly acquired and those that have left. But all are just indicators of "potential" performance, metrics it is not a science, just a mathematical application of probabilities. These are made on various assumptions as to the weighting ( relevance ) of the data. Some have become stronger indicators than others, but they aren't exact. They can't be, because they are based on the performance of human beings which involves a totally different set of criteria. Basically its their mental capabilities, mind set, attitude etc. This is why psychology is an inexact discipline, there is no definitive way to accurately judge a person's mental state, nor how to correct it. For instance is he worried about his marriage, family, health ( injuries he's been hiding due to contracts, his future, etc. ). Basically, a positive mental attitude, relates to confidence in your ability. There is no current statistic to measure this. Although, we all heard of phrases like; "I'm seeing the ball better", " I'm in a hot streak", "The ball just isn't droping in", ect.
I guess what I'm saying, as a sports fan is, my team is the Red Sox, and every year is a new year and starts with a clean slate. This means that, I hope the injured heal, new acquisitions perform as expected ( or better ), and the rookies live up to their hype. A true fan never goes into a season saying things like; " we're going to suck" or " the only way we're going win is if other teams are decimated by injures". I ,for one, enter this season with my eternal optimism.