Those leaders are not universally exceptional players, although Adam Dunn in particular had a lengthy and productive career in which he counterbalanced a lot of those strikeouts with home runs and walks. However, beyond even Dunn, there are a number of truly extraordinary hitters who have had streaks of 12 strikeouts in 19 at-bats. For example, Giancarlo Stanton has done it 16 times since 2007. Freddie Freeman has done it seven times. David Ortiz has done it five times.
I’m sure it made it easier for the Red Sox to trade Moncada after his strikeout streak, but this one small sample-size performance is not out of the ordinary even for some of the best players in baseball.
Methodology: There is more than one way to account for the number of times batters recorded 12 strikeouts in 19 at-bats. We opted to count each unique instance of 12 strikeouts in up to 19 at-bats as unique streaks. That means that some strikeouts become a part of more than one streak for hitters, but the exact sequence of 12 strikeouts is not counted more than once even if it occurs in fewer than 19 at-bats.
This is probably best illustrated with an example. Take the following 19 at-bat stretch for a hypothetical hitter:
KKKOKKKOKKKOKKKOKKK
Where K represents a strikeout and O represents a non-strikeout. We counted each of these as separate streaks:
KKKOKKKOKKKOKKKOKKK
KKKOKKKOKKKOKKKOKKK
KKKOKKKOKKKOKKKOKKK
KKKOKKKOKKKOKKKOKKK
However, we did not count any of the "more than 12-strikeout" streaks that occur in that 19 at-bat sequence as separate streaks.