Let’s start from square one. There are a lot of metrics that are important to the game of baseball, but perhaps the single most important metric is on base percentage. That’s because baseball is unique among major sports: there’s no timer. Rather, the game ends when its finite supply of resources–outs–are all gone. Avoid outs for longer and you’ll score more. Force the other team to make outs more often and they score less. It’s that simple.
While there are a lot of results from a plate appearance, pitchers are in control of two of them: walks and strikeouts.