This came up in coversation during game 6 of the World Series.
What is the point of having the yellow homerun line along the outfield fences? It seems that all it does is make the call much more subjective and difficult. Without the line, the call seems easy – the ball either stays in the park (not a HR) or it leaves (HR). But instead, you have to go by the ump’s “did it hit here? or here?” call.
Is there some advantage to the yellow line that I am overlooking? Why was it put in place?
The advantage is if the ball tips the top of the fence as it goes into the stands. You could have a very lively argument whether that should be considered a ground rule double (i.e., the ball hit in the field of play and then went out) or a “true” home run. So if the ball hits the yellow line and bounces out, argument over, it’s a home run.
Again, maybe there’s something I am missing, but it seems cut-and-dry to me – if the ball hits the wall and goes over, it’s a HR. Obviously, if it hits the ground first, it is a GRD. Why would there have to be a debate about it?
There exists the possibility that the ball COULD hit the top of the wall and (because of stitches on the ball, direction of spin, angle of deflection, etc) have the ball bounce back into the field of play.
Once the ball touches the yellow line, it’s a home run.
Same thing with the foul poles. If a batted ball makes contact with a foul pole, it’s a home run.
The Foul poles make sense, as there is no good way to judge a fair or foul bowl that is hit into the stands and is close.
But, in the other example you gave, (Ball hitting the top of the wall and coming back) then why not make it a live ball?
It is, in some ballparks (most notably in Yankee Stadium in last year’s series 
).
Why do it the other way? Because that’s the way the home team wants it.
Could you provide a picture, or description, of the line you’re thinking of? All parks are different. Any time I’ve seen a line on a wall it was an extension of the top of a wall that went behind another wall that jutted away at an angle. Most fences do not have “yellow home run lines” at all.
I know Bank One Ballpark in Phoenix has a yellow demarcation line at the top of the centre outfield wall. However, the wall “above” that is not supposed to be part of the outfield fence; that is there as a hitting background, so it’s not like they just arbitrarily split the outfield fence in half with a yellow line. The line makes it easier for umpires to see where the outfield wall ends and the hitting background begins. There are also yellow lines painted above the edge of the outfield seats that indicate where the outfield wall ends and where it beocmes merely the wall behind the bleachers; this makes it easier for the umpire to determine if a fly ball has struck the wall proper (in play) or actually went over the seats and struck the part of the wall behind them (a home run.)
Also, in Bank One, a ball that actually touches the yellow line is IN PLAY. In all parks a ball that bounces off the very top of the fence and bouces back into the field without striking anything else, such as a part of the wall behind the top of the fence, is usually not a home run, but a live ball. The one exception I can think of is the right field wall in Baltimore, part of which has no top per se; the top of the wall is the roof of the ground crew shed, which is ten feet deep or so, so any ball landing atop the shed is considered a home run according to Camden Yards ground rules.
RickJay,
But it seems to me I have seen stadiums where there is a yellow line along the top of the outfield wall, and that it’s possible for a ball to hit near the top of the wall and then be ruled a HR (because it hit the yellow line).
I’ll look for some pictures.
Jacobs Field has the yellow line you describe. It is visible at the right of the top photo at this page. The line does continue up along the bleachers, but you can’t see it because it is in shadow. You can see it pretty well in this photo.
Not every stadium has a yellow line. In the majors, I think the yellow line is in a minority of stadiums. They are used when the fence is built in such a way that it can be difficult for the umpires to determine whether or not the ball has gone over the fence.
For another take on this subject, see what you can find about a Houston Astros game at Enron in about August or September 2001. Moises Alou hit a line drive off the scoreboard in left field. There is a small “lip” between the top of the scoreboard apparatus (which is a billboard) and the bottom (which is a out-of-down scoreboard like Fenway’s Green Monster) – about 20 feet off the ground. The ball caromed nearly straight up but with just enough topspin that it landed in the stands a few rows back. After much consternation, it was ruled a homer. It didn’t make as big headlines as it could because the next batter hit a double or something and as such Alou would have scored even if it had been ruled a ground-rule double. An interesting situation and ruling.
However the Jacobs Field Ground Rules say:
They don’t say anything about a ball hitting the yellow line and coming back into play so I can only assume that it would be a fair ball.
The yellow lines are not part of baseball’s rules. As he says, it’s up to the home team to decide if they want to use them.
This is what managers and umpires are talking about before the game when they exchange lineup cards and discuss ground rules.
Perhaps I was not sufficiently clear; a ball that hits the yellow line is not a home run. There is no such rule in the Official Rules, and EVERY mention of yellow lines in he ground rules of existing major league parks state that balls that hit yellow lines are IN PLAY, not home runs.
“Foul pole” is a misnomer. Should be called a home run pole!
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“You can observe a lot just by watching.” – Yogi Berra
I know at least one commentator has acknowledged the misnomer and calls it the “fair pole”.
