The Mets probably did need another reliever to rest their beleaguered bullpen. For that reason, calling up Nelson Figueroa makes some sense, in the abstract at least. Swapping Jon Niese for Figueroa straight up, however, does not, and reflects poorly on the organizations ability to evaluate pitchers. Assuming that Figgy will either make the rotation or get sent down shortly for Tim Redding, why not just demote or release Livan Hernandez?
Well the probable answer lies in ERA. Livan Hernandez sports an unspectacular, yet not altogether embarrassing 5.08 mark. Niese, on the other hand, has a 6.55 ERA in AAA Buffalo. Seems pretty simple to most people: Niese has potential but needs more seasoning. This situation, however, is a near-perfect example of why ERA is not a good statistic. Below are the important criterion for evaluating pitchers, as per USSM's "Evaluating Pitcher Talent" guide. Many of you may already know this stuff, but it's important.
BB% (Walks per Total Batters Faced) does a nice job evaluating how often a pitcher throws the ball in the strike zone. The average walkrate is 8% for a major league pitcher, though the DH makes the AL a higher walk league than the NL. Anything under 5% is tremendous, and anything over 11% is a problem. The Hardball Times publishes BB% and K% in a slightly different manner, calling it BB/G or K/G to make it scale more like the per nine innings numbers people are used to seeing. BB/G (and BB%, its derivitive) is more effective than BB/9 because it accounts for the actual amount of batters faced rather than using a proxy like innings pitched. It’s just more accurate.
K% (Strikeouts per Total Batters Faced) does a decent job evaluating how often a pitcher induces swings and misses or called strikes. 16% is league average, with 20% being terrific and 12% being a problem.
GB% (Groundballs per Balls In Play) does a very good job of telling us how often a pitcher induces a groundball. 42% is league average, and anything over 50% is terrific, with the best sinkerball pitchers posting rates in the 60-65% range, while anything below 35% can be a problem if its not offset with a high strikeout rate.
LD% (Line Drives per Balls In Play) does a very good job of telling us how often a pitcher gives up line drives. 20% is league average, 17% is good, and 23% is a serious problem. Because of the way line drives have been scored by Baseball Info Solutions the past couple of years, this number is hard to use for year to year analysis, and right now, it’s not a very effective tool. We don’t use it very often.
FB% (Flyballs per Balls In Play) does a very good job of telling us how often a pitcher gives up flyballs that leave the infield, and is basically the corollary to GB%. 36% is league average, while 32% is good and 40% could be a problem.
Now apply those benchmarks to Niese's performance at two levels this year:
According to Cameron's guide, Niese's K% and GB% rate are both terrific, while his walk rate ranged from average in AAA to tremendous in his extremely small sample size with the big club. tRA measures what a player's ERA should be, absent defense and luck. It's a better measure than Fielding Independent Pitching (FIP), because it accounts for the different types of batted balls, like GB%. Both of those marks, small sample size or not, are obviously fantastic. Any pitcher who can combine a high GB% and K% will be successful in the major leagues. His FIP from his two major leagues starts is a tiny 1.90, as almost every type of bad luck, a high BABIP and a low LOB%, went against Niese. He could very well be the second best pitcher on our team, if given the chance. By contrast, Livan has just a 5.47 tRA, which sadly, isn't bad for him.
Using these numbers, the difference between Hernandez and Niese in the rotation can be estimated. Let's assume Niese would maintain a tRA of 4.00 in the majors, which is not overly-optimistic. And let's also assume Livan keeps up the 5.50 pace, which knowing his ability to fade away, may be optimistic. Over the course of 120 innings, Livan would allow 73 runs, while Niese would allow 53. The difference, of course, is 20 runs, which is about 2 whole wins. In this division, I think everyone understands the importance of 2 wins.
Over the course of the season, Niese's talent should prevail over bad luck and bad defense, but the Mets need him to do that now in the majors, not in Buffalo. Development is all-but over for Niese, he just needs to be allowed to pitch, not shuttled around like Heath Bell. Some argue he should build up confidence with a few more successful starts in Buffalo, but he is fighting an uphill battle with players like Mike Lamb, Bobby Kielty, and Willy Mo Pena fielding behind him. Ultimately, the best move for his confidence, and the Mets success, would be to insert him in the rotation now, ditch Livan, and let Redding hold Oliver's spot. I doubt that happens, but it really needs to. Free Jon!