Over three seasons I have ranked Cub pitching prospects according to the Marmol Index, or strikeouts per nine innings minus hits per nine. This has been a good predictor of success for pitchers likely to join Marmol in the Cub bullpen, such as Maine, Gaub and Beliveau, three lefties on the current 40-man who have a chance to make the big-league staff this season. Gaub and Beliveau have been at or near the top of the Marmol Index since the middle of 2009.
The list has a couple of flaws. One is a bias in favor of relievers, who don’t have to pace themselves and can bear down harder on the handful of hitters they see. Relievers also can get away with a degree of wildness that would doom a starter. Wildness can be a weapon in the arsenal of a strikeout pitcher. If he falls behind a hitter, a wild reliever can just walk him and try to get ahead of the next guy. It works for Marmol (most of the time). A starter can’t put runners on every inning and expect to stay in the game very long.
The best Cub pitching prospects right now might be relievers, but not the nine or ten best. If you look at the current Marmol Index in the right margin of this page you will see the names of nine relievers before you get to the first starter, Cameron Greathouse. (Aaron Kurcz, number seven on the list, is actually a sometime starter who averages two-and-a-half innings per game.) It is true that after the 2010 season, three starters–Cashner, McNutt and Archer–came in 3rd, 4th and 5th in the Marmol-index rankings, but that was an unusual collection of starting talent which, in any case, should have finished 1-2-3 rather than 3-4-5 in any serious ranking. The table below is a new version of the Marmol index that tries to correct for the bias against starting pitchers.
The 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. In the table, Weathers (1.04) and Gaub (1.11) come closest to exactly an inning per appearance. Whitenack, Rhee and Kirk pitched into the sixth inning, on average, in their games, while Coleman lasted into the seventh, overall, in his twelve starts for Iowa.
The result of the adjustment is that while Greathouse is still #10, starters Liria, Whitenack, Rosscup and Loosen are 4 through 7, while Cates, Jokisch, Coleman, Rhee and Kirk are in the next ten.
The other flaw in the Marmol Index is that it overlooks walks, so that Gaub and Greathouse and Casey Weathers, for example, as well as Marmol himself, can rank high in the list in spite of having certain numbers, like WHIP and BB/9 and K/BB, that flash in red. I am inclined, though, to continue to treat this flaw in the ranking system as a kind of virtue. A good formula should be simple, and therefore can’t be universal. Here we are seeking out good arms, not good aim. Gaub will probably be a major leaguer this season at 27, and Weathers, who is also 27 and would have been fifth on the list by the old formula, will get a fresh start in the Cub organization. One mark of prospecthood is the size of your window. Lesser prospects than Gaub and Weathers would have disappeared by now. Greathouse, by our measurement, is a real prospect, in spite of a K/BB ratio below 1 and a midseason demotion from Peoria to Boise. He was only 20. A pitcher’s command tends to improve over time, unlike, say, his fastball.
Jeff Beliveau was 21 in 2008 when, as a junior at Florida Atlantic, he struck out 78 and walked 77 in 76.2 innings, and fell to the 18th round in the draft. But his arm made him a prospect and today his control is no longer an issue. His WHIP last season was 0.93. Command-wise, Marmol himself is still a work in progress, but the promise of an elite closer was always there.