Something that a lot of managers often use to justify a guy playing on a given day is that they "have success" against a particular pitcher.
While there are a lot of other things from this fantastic article on Farhan Zaidi, director of Oakland Athletics Baseball Operations, this one stood out to me because it isn't something you see discussed much.
I would highly suggest reading the entire article. Some real interesting things in there.You don’t want your manager necessarily viewing a match-up favorably if a guy is 2 for 3 against somebody. It’s the same sort of sample-size challenge that comes with advanced reports.
“We try to analyze skill, not results. Ultimately, what you want in an advance report isn’t batting average on fastball counts. You want something more along the lines of skill level, like how often a guy makes hard contact on a fastball on an 0-1 count. That approach is very applicable in this area.”