Cleveland Indians’ ace Justin Masterson pitched a great outing on Monday, throwing 7 innings of shutout ball with 10 K’s and just 3 hits. The most impressive part of his day, though, came during the top of the 4th inning when he threw an immaculate inning. For those who don’t know what that is, it’s when a pitcher records three outs by striking out the side on 9 pitches (9 pitches, 9 strikes, 3 strikeouts). Masterson is only the 70th pitcher to accomplish the feat and the first Indians pitcher to do so.
Hence the term, immaculate.
[MLB.com]