50 PA: Swing %
100 PA: Contact Rate
150 PA: Strikeout Rate, Line Drive Rate, Pitches/PA
200 PA: Walk Rate, Groundball Rate, GB/FB
250 PA: Flyball Rate
300 PA: Home Run Rate, HR/FB
500 PA: OBP, SLG, OPS, 1B Rate, Popup Rate
550 PA: ISO
For the uninitiated, that's how long it takes for a statistic to become reliable. Rizzo seems to be taking some more pitches. But we are still a ways out from being able to reliably predict what impact that's going to have on his strikeout and walk rates. It's way too early to freak out.