When watching or playing a baseball game, you may hear this term: “45 Degree Line”. This is used when deciding on a balk call with a left handed pitcher. However, does this rule (and the term) appear in the rules? Let’s see…

Many people take this “myth” personally. Search the term on the internet and you’ll find plenty of discussion. In fact, one of my favorites is on an Adult Baseball Umpires Association site, that says this:

“DID YOU KNOW that there is No Such Reference in any official baseball rule book on the planet Earth that addresses, or infers whatsoever, that a left-handed pitcher has some imaginary 45-degree mound line that establishes some kind of “no balk zone” with reference to where and how he steps when throwing over to 1st base during a pick-off attempt? No way, no how—zero, zilch, nothing, nada. Period, the end. Really.”

Really? “Period, the end”? That’s a strong statement – and it’s wrong. Period, the end (sorry, I couldn’t resist).

The term “45 Degree” does appear in an official baseball rule book – in fact it appears in 2 of the 3 rule sets – it just takes some research and the knowledge that OBR isn’t the ONLY official rule book! [note: see our article Understanding the Rules of Baseball - Rule #1]

It appears directly in the NCAA Rules and it appears in the NFHS Case Book. The Case Book is official per the NFHS:

“Rulings in this book are approved by the NFHS Baseball Rules Committee. They are official for situations outlined”

The rule reference for NCAA is NCAA 9.1.a.6:

“Directly” is interpreted to mean within a 45-degree angle measuring from the pivot foot toward the base the pitcher is throwing to or feinting a throw.”

The reference is NFHS Case Book 6.2.4 Situation B. Here’s the quote:

“To comply with the requirement to ‘step directly toward’, F1 must step to the first-base side of a 45-degree angle between center of pitcher’s plate and between home and first base (6-2-4b)”

But, let’s go back and explain exactly what 45 Degree means in relation to a pitcher and balks.

In all rule sets, the pitcher is required, when making a pick-off throw or fake, to step directly toward the base he is throwing to. Again, for our purpose, we are discussing a lefty throwing to first base. [ OBR 8.05.c; NCAA 9.3.c; NFHS 6.2.4.b ]

The phrases “directly toward” (or similar) leaves room for interpretation (as is very common in baseball rules). All the rules say that a pitcher must gain “distance and direction”. Distance means that his non-pivot foot has come completely of the ground and lands in a different location, while direction means the foot went toward the base. [ PBUC 6.6 ]

Gradually, over time, the organizations have accepted that a lefty must have his non-pivot foot (his right foot) land to the first base side of a line drawn from the pitcher’s plate to the first base line between home and first base – forming 45 degree angle when measured at the point where this line meets at the pitcher’s plate with a line directly from 1B.

The pitcher’s right foot must land on the first base side of this “line” to be considered as having stepped directly to the base.

We’ve already given the reference to the NFHS rule and the NCAA rule that makes the 45 Degree line legitimate.

So, is it a myth in OBR? Yes – and no! Yes – in that the term doesn’t appear in the rules. No – in that it is the generally accepted way the call is made on a left handed pitcher. In fact, in a Major League spring training season years ago, the league had a 45 degree line drawn to aid the umpires in properly calling this a balk or no balk. No one liked it and the idea died.

Now, you may feel that using this 45 degree line as a guide isn’t fair or right – “it’s not in the rules!” – but this is the nature of the baseball rules. Not every thing is cut-and-dried. Interpretations and case books are needed to navigate your way through this maze!