Pitching statistics can be both mind-blowing and downright confusing. As compared to the step-by-step evolution of batting statistics, pitching has many more scenarios and external factors surrounding its key stats. None of which proves that better than the long time cornerstone of evaluating a pitcher: Earned Run Average.
Earned Run Average (ERA): The amount of earned runs given up by a pitcher per nine innings pitched (9 x Earned Runs Allowed / Innings Pitched).
9 innings is the amount of innings pitched in a regular game, therefore it becomes the base in which all pitchers are evaluated equally on. Whether it be a starting pitcher who goes 7 innings, or a relief pitcher who only lasts 2/3 of an innings, both will be valued on the same scale.
A key word within this statistic to not overlook is “earned”. In pitching, there are Runs Allowed and Runs Earned. The former reveals how many runs are scored against a pitcher, but the latter reveals how many of those runs were responsible by the pitcher. Unearned runs are such that results in a run scored or a batter getting on base through an Error; any of such is no longer the pitcher’s responsibility regarding his ERA.
Many factors in baseball can seriously impact a pitcher’s ERA before he even takes the mound, most of which do in fact cloud the once vital statistic.
A starting pitcher will more likely suffer from the Runs Earned factor of ERA; more often than not exiting the game during an inning, whilst leaving runners on base. Those baserunners are still his responsibility; even though he can no longer physically allow the run, the starting pitcher will be struck with the earned runs if they were to score. This will give relief pitchers a greater advantage of maintaining a lower ERA, for they can allow runs that were already on base before they took the mound. Relief pitchers know beforehand how long they will be pitching for, as well as being aware of the situation that they will walk into. Starters do not have the luxury of entering a game half-way through, nor can they save up their energy for merely a handful of batters in a short spell.
Another external factor is what ballpark a pitcher is playing under. Ballparks such as Yankee Stadium (Yankees), Minute Maid Park (Astros) and Miller Park (Brewers) are considered big-hitting locations due to their shortened field dimensions. Coors Field’s (Rockies) ridiculous altitude (1600m above sea level) results in thin air, meaning that the baseball travels further on a fly ball that undoubtedly results in more home runs allowed. Such factors can result in a routine fly ball turning into a home run, meaning more earned runs on a pitcher’s ERA.
A typically good ERA for any pitcher is any value below 4.00. But don’t immediately judge if a pitcher posts an ERA of over 5 when pitching under such short-field environments. Pitching environment works the other way also. AT&T Park (Giants) and Petco Park (Padres) sport some of the largest field dimensions in the league, meaning fewer home runs and more fly ball outs in the outfield. The flaw within this factor is that most pitchers will find themselves pitching under a different ratio of environments, therefore they cannot be valued equally based on how often they pitch in different ballparks.
But don’t guarantee that just because a pitcher pitches with a large outfield behind him will result in a lower ERA. As many Giants’ pitchers have showcased within the past few seasons (Barry Zito, Tim Lincecum and Matt Cain), you don’t necessarily need to give up home runs to create a sloppy ERA. More outfield grass means more possibility for line-drives turning into base hits and extra base hits, meaning more runs allowed.
The final factor to take into account is the league in which the game is played under. From 1973, the American League introduced the Designated Hitter position, replacing the Pitcher in taking plate appearances whilst the latter continues to pitch on the mound. Pitchers in the American League must pitch against another significant batter, rather than the typically lifeless starting pitcher under National League rules.
Starting pitchers in the National League will generate a lower ERA than their counterparts in the American League. But, it’s important to realize that this only applied to starting pitchers. By the time relief pitchers enter the game in the National League, pinch hitters would typically replace the retired opposing starter; relief pitchers very rarely have to take a plate appearance between innings.
Nonetheless, there are severe flaws surrounding ERA for it to be a precise statistic towards evaluating the entire situation surrounding a pitcher’s performance. It remains a fundamental statistic, for it is one that promotes the impartial evaluation of all pitchers under the same formula. What’s more, it continues to emphasize an essential notion towards winning in baseball: keep the other team from scoring.
So if you have to pitch at Yankee Stadium for over half of your season? Tough. Find a way to pitch well.
Walks and Hits per Innings Pitched (WHIP): A very effective statistic towards measuring a pitcher’s effectiveness against batters in a more direct manner than ERA. Simply, WHIP is calculated by the amount of Base on Balls and Hits allowed by a pitcher and divided by Innings Pitched (BB + H / IP). This is a fantastic sabermetric statistic that has become most popular within fantasy baseball in recent years.
It promotes the notion that by allowing fewer batters to get on base, the more effective that pitcher is towards generating wins for his ball-club. The best way in evaluating a pitcher’s WHIP is to eliminate any relation to his ERA. A pitcher can still post very poor numbers in his WHIP (over 1.5), but this reflects how many batters he puts on base per inning, not how many score against him. ERA can be restricted by a combination of fielding and base-running decisions that are out of the Pitcher’s control. WHIP is measured far before those factors can be put in play, hence why it is an important stat is monitor.
Fielding Independent Pitching (FIP): The pitching equivalent to Weighted On Base Average (WoBA), where linear weights are implemented within three true outcomes for a pitcher in an at-bat.
FIP = (13 x HR) + (3 x BB) – (2 x K) / IP + constant
The equation measures a pitcher’s performance that strips out the influence of defence and luck, towards providing a more stable indicator during a given period of time. Just with ERA, a lower FIP the more effective the pitcher, hence why we subtract the linear-weighted Strikeouts (K) and provide an incredibly bloated weight on Home Runs (HR).
By constant, we refer to the key notion that FIP is designed to run in parallel with ERA, by which both stats are of equal value through the League Average ERA (lgERA). Here is the advanced equation in order to discover the FIP constant:
FIP Constant= lgERA – (13 x lgHR) + (3 x (lgBB+lgHBP)) – (2*lgK) / lgIP
As you can see, using the league average’s in Home Runs, Walks, Hit by Pitch, Strikeouts and Innings Pitched, we are able to either chip away or bulk up the league ERA towards providing the constant FIP throughout the season. This is not only an effective way of measuring how effective a pitcher is as an independent performer against follow pitchers in the league, but comparing the value of the FIP constant from season to season.
Strikeout per Walk ratio (SO/W): Similar to WHIP, the ratio of Strikeouts per Walks allowed is an effective statistic towards measuring how effective a pitcher is against a line-up, well beyond the aspect of how many runs are allowed. This ratio specifically determines how effective a pitcher is at getting batters out at the plate over how often he allows them to get on base. The key phrase is “at the plate”; base hits are obsolete in this spectrum, as is any other event that occurs outside of home plate.
Aggression and control on the mound are two key traits that are tested within Strikeout per Walk ratio. We all enjoy 100mph fastballs, but if a pitcher cannot control such velocity then his effectiveness against batters shrinks significantly. To be able to command pitches and tallying a high SO/W ratio; converting strikeouts and avoiding errant pitching towards allowing walks is what separates elite pitchers.
In addition, the ball-park factor cannot influence a pitcher’s SO/W, for fielding dimensions and the triggered effects on fielding and defence do not affect the number of strikeouts and walks produced on the mound. While the field lengths vary from every ballpark, the dimensions within the infield do not. It’s still 60 feet and 6 inches from the same-sized mound to the same-sized home plate, whatever ballpark a pitcher plays in.
Strike Percentage (Str%): Speaking of Strikeouts and Walks, a fundamental element of generating good values of both, as well as pitching effectively in general, is throwing Strikes. In short, you can’t be a pitcher if you can’t throw strikes. The figurative rectangular zone that sits slightly below the batter’s chest and at his knees, in parallel with the width of home plate that pitchers aim for is the bread-and-butter of command and control on the mound.
Str% is a very self-explanatory statistic: the amount of strikes within pitches thrown. But it is the ramifications of its outcome that makes it an effective one to monitor. Because of the variety of outcomes, both positive and negative, that can derive from throwing a high or low number of strikes, Strike Percentage acts as an excellent figure that can connect to other key statistics towards discovering the method of a pitcher’s effectiveness.
For example, if a pitcher tallies a high ratio of Strikeouts, his Str% will be able to indicate exactly how often he is pitching strikes towards achieving so many strikeouts. A high percentage would create the assumption that he is getting batters to swing for his pitches, while a slightly lower percentage would indicate either a variety in make-up/repertoire, but also a very loose control.
This would also indicate the same for Hits; a high Str% would indicate too many hittable pitches, whereas a lower value could indicate that hittable pitches are being thrown, but influenced significantly by the lack of pitches finding the strike-zone.
Strike Percentage puts a figurative detective’s cap on one’s head and activates the role of investigator towards finding the method of a pitcher’s effectiveness. After all, strikes are the fundamental aspect of all pitching outcomes, and Str% clearly reflects such a notion.