So luck is now a quantifiable statistic too?
When talking about percentages compared to the averages, yes. One pitcher having a .375 BABIP against him, especially if pitch type, contact % etc. aren't out of whack, would be considered bad luck.
For a batter it would be the guy who keeps lining out. Compared to the league averages you can find guys whose luck was better/worse than others and track it to see if their result stats improve once those measurables return to normal.