You can’t expect the GM to improve on something that hasn’t happened yet. He have the future to look at. If a player improves elsewhere, there could easily be other factors involved. Are Wacha and Eovaldi benefitting from better defenses? Or better coaching? Is JD hitting better because of worse pitching or the ballpark or being buried in a better lineup?
Other than the defenses, I don’t know of any of these are true. But they are all certainly possible…