# Baseball question--what is ERA?

I should know this by now…but I don’t. I know it’s a pitcher’s average, but is that based on the number of hits the batter makes vs. the number of pitches thrown? I keep wondering about exceptions…does the hit count if it’s a foul ball? An out? Does the batter have to make it on base?

Or even score? Is that what’s meant by earned RUN average?

/silently ashamed of my baseball ignorance.

ERA : earned run average. The amount of earned runs a pitcher would normally give up in a nine inning outing (on average).

Calculated as follows:

(number of earned runs allowed * 9) / innings pitched

So if Roger Clemens has pitched 16 innings and has given up 3 earned runs, his ERA is (3 *9)/ 16 = 1.68.

Earned RUN Average does exactly what it says on the tin. The batter does indeed need to score, hence the word ‘run’, but not even all of these count towards the average. The run must be earned by the pitcher - that is, he was responsible for the man who scored reaching base on a hit, walk, hit by pitch. If the pitcher is not at fault for the man reaching base, for example where a simple throw to 1st would get the batter out on a ground out but the 1st baseman drops it, then if that runner scores, its not earned. Makes sense - not his fault.

Anyway, the number of earned runs he gives up every 9 innings of work (hence the word ‘average’) is his ERA. An ERA of 3.00 means 3 runs score in 9 innings, so 1 run every 3 innings and so on.

Hopefully this is of assistance, but I’ll have to pass this on, regarding the technicalities of earned runs, to someone who’s a real expert.

To clarify, some runs are considered earned and some unearned. Unearned runs are when a defensive player makes an error (a term that has a definite meaning in baseball, in that the player’s mistake allowed a player to reach base who would clearly have been out on a normal play).

If a runner reaches base on an error, it doesn’t count as an earned run if he scores. And if the error would have been the third out in an inning, all runs after that hypothetical third out are also unearned. In other words, if the first batter reaches first on an error, it’s an unearned run if he scores. In addition, after two outs, any runs scored are unearned (because that error on the play would have meant the third out would be recorded when the second out was).

Unearned runs are not counted for the earned run average.

My memory is a bit foggy, but…

If pitcher A fills the bases, and is pulled out of the game in favour of reliever B, and reliever B makes an ass of himself by allowing a grand slam on the first pitch, I believe three of the four runs are earned by pitcher A. No?

Also, if a pitcher leaves the came, any runners he allowed to reach base are still his responsibility and count against his ERA if they score. For example, if the pitcher gives up a double and is then pulled from the game, if that runner subsequently scores it will still be counted against him, not the relief pitcher.

Wow! Telemark managed to simulpost the answer to my question. That ain’t ERA, that’s ESP!

I was wondering how partial innings are counted for ERA.

Assume opening day a pitcher starts the game, and gives up a leadoff double then a home run, and is immediately pulled. What’s the ERA for 2 earned runs in 0+ innings? (and what if he had gotten one out before being pulled?)

He’d have an infinite ERA, in 0+ innings. If he had gotten one out, and 2 ER, then he’d have an ERA of 54.00

Innings are measured in thirds, with each out marking a third, no matter how many batters are faced to get the out.

This could, indeed happen. If a pitcher were called up from AAA, started a game, gave up two earned runs without getting anyone out, was pulled and sent back down to AAA never to be called back up he would go down in the Major League record books as having an infinite ERA.

You will frequently see, in the early season, otherwise good pitchers with very high ERAs just because they had a few bad outings in early games.