This table derives from the original Marmol Index, which was simply K’s per 9 innings minus hits per 9 innings. Marmol deserved to have the index named for him since he always had the widest possible spread between strikeouts and hits-allowed. (We don’t look at bases-on-balls here, on the theory that a pitcher’s command can improve more markedly than his stuff.)
The revised table adds three columns to the old index. The new fields are games, innings per game, and at the far-right of the table, an “adjusted” K/9-minus H/9 that gives a pitcher credit for his number of innings per appearance. The new formula, according to which pitchers in the list are ranked, is K/9 minus H/9 plus (innings-per-game minus 1). According to this formula, if a pitcher throws exactly one inning per game, there is no adjustment to K/9 minus H/9. More than one inning per game, his number is adjusted up. Fewer than one inning, it adjusts down.
The reason for the adjustment is that the old index favored relief pitchers, pitchers who make brief appearances per game. Relievers can be good prospects but in any serious ranking they should give way to top starting prospects, who must pace themselves and pitch more to contact. So we jigger the numbers to help the starters.
Coming back strong from Tommy John surgery late last season, Rosscup is promoted to Tennessee and vaults to the top of the Marmol Index with a K/9 of 16.3 after 14.1 innings pitched.