Looking at Rosario's postseason, his slash line looks incredible but in some ways not unlike his regular season streaks I mentioned in my previous post:
68 PA, 14.7% K%, 7 XBH
His first 5 postseason games this year, he had 5 singles (1 in each game), zero XBH, zero non-intentional walks, and only 2 K's.
Then NLCS Game 2 he collected 4 straight singles, but pretty much continued his contact approach. Video of all 4 singles here. Two infield singles -- one he barely beat on replay review, and another which could have been an error (off the infielder's glove) -- plus another poked through the left side of the infield to beat the shift.
Next game, a leadoff single was followed by two non-intentional walks later in the game, and the game after that, he collected 3 XBH, his first of the postseason.