Last week, we looked into the arithmetic of batting statistics. While batting is probably the most basic way to gauge a successful game of ball, sometimes it seems that we forget that this is much a pitcher’s game as it is a batter’s.

After all, if there isn’t a pitcher, how would a batter be able to hit a thrown ball?

And just like batters, pitchers have their own statistics that are important to follow and keep in mind. They are important because of pairs: If you have a good pitcher throwing to a good batter, it will probably be an intense at-bat. If you have a good closer on your team paired against a winning yet crumbling opponent, you will probably be more than excited to see if the game can be salvaged.

So, let’s get on the mound and figure out the basics of pitching. Once again, I will try to make this as simple as possible for the number-phobes.

First and foremost, know that there are different kinds of pitchers: starting, relief and closing. Starting pitchers are self-explanatory; they start the game for pitching. They are often times the strongest pitchers on the team because they can throw for the longest time with the most strength.

Relief pitchers step in, if necessary, to relieve the starting pitcher when his throws get weak. They will usually make their appearance around the fifth or sixth (sometimes even sooner) inning and will go until the end of the seventh inning.

Closers finish out the game. These guys are all brains and brawn and are intended to bring that rush of first-inning energy back to the game to shake up a fatigued team. They come out in the very last innings of the game.

There is always the chance, though, that a reliever and/or closer won’t appear. No-hit games are tough and rare but possible. And of course, a relief pitcher can end up closing a game, too. It all depends on the throws and energy of the pitcher.

Now, onto the numbers. I’ve picked Roy Halladay (Phillies) as an example, as he is probably one of the better (if not the best!)  pitchers in the majors from 2011.

Now, here you will see a plethora of information, but the most important things to note here (and with any pitcher page on ESPN.com) is the letter set next to his jersey number as well as what he throws and bats.

Here, we have SP — that means he is a starting pitcher. He throws and bats right (R). Simple enough, right?

Now, with those basics in mind, off to the right you would see a box that looks like this:

These are his pitching statistics for 2011 (and below them, from his entire career).

The ERA is the “earned run average,” which is figured by the total number of earned runs multiplied by nine divided by innings pitched. Earned runs are the number of runs that did not occur as a result of errors or passed balls — in other words, runs that happened simply because the batter “earned” them by hitting the pitch.

In this case, lower is better. Fewer mistakes in pitching and more appearances will create a lower ERA. Currently the lowest ERA in the majors is held by Yankees pitcher Mariano Rivera, who has a 2.21 career ERA.

Comparing Rivera’s 2.21 to Halladay’s 2.35 means that Halladay threw one hell of a 2011 season.

Now, the W-L is a win-loss stat. A win (W) comes from the number of games won while the pitcher was pitching. The catch: The starter needs to pitch at least five innings of work. The loss (L) is the number of games where pitcher was pitching while the opposing team took the lead, never lost the lead and went on to win. So, in other words, it’s the games where Halladay was pitching and the opponents took the lead and won, giving the Phillies no chance to pass into the winning position.

So Halladay pitched 27 games where he played for at least five innings, 19 of which he contributed to the win. This is a good thing — more wins is better. If you look at his career stats, that’s where it shows the most. Look at the number of wins!

SO stands for strikeouts. This is sometimes noted as K. Strikeouts, in the case of pitchers, is how many people they struck out (three strikes, you’re out — you know how that goes). More is good for a pitcher – and Halladay has struck out nearly 2,000 players in his career.

Woof.

Now, the final statistic: WHIP – walks and hits per inning pitched. Basically it is a measure of the ability to prevent a batter from reaching a base. It’s the sister statistic to ERA, in theory. ERA measures losses and WHIP measures why. You add up walks and hits given up by the pitcher and divide them by innings pitched to get a WHIP.

Low WHIPs are the best – that shows efficiency in keeping runners off of bases and skill in pitching (no balls or runs).  A WHIP below 1.00 is considered exceptional and very strong – Halladay has a very low WHIP for the 2011 season.

So — there you have it. Pitching stats! They’re a little simpler than batting statistics, but there is always more to pitching than just numbers. Perhaps pizzazz will someday be a statistic too – but who knows.

Anything can happen in baseball, folks.

Screenshots captured from ESPN.com