Balk rules

Assuming a left handed pitcher.  If RH, then he'd have to step off before making the throw to first, so, as a fielder, no balk.

If a LH pitcher, it's a balk if he didn't first step off the pitching rubber.

It's covered under 8.05(c), but requires additional comment from the MLB Umpires Manual.  8.05(c) states:  

The pitcher, while touching his plate, fails to step directly toward a base before throwing to that base;
Rule 8.05(c) Comment: Requires the pitcher, while touching his plate, to step directly toward a base before throwing to that base. If a pitcher turns or spins off of his free foot without actually stepping or if he turns his body and throws before stepping, it is a balk.
A pitcher is to step directly toward a base before throwing to that base but does not require him to throw (except to first base only)

So you can see that this applies to LHP since it specifies being in contact with the rubber.  The Umpire's Manual provides additional comment that:

The pitcher shall be charged with a balk if, while in contact with the rubber, he throws to the first baseman who is either in front of or behind first base and obviously not making an attempt at retiring the runner at first base. However, there is no violation if the pitcher throws the ball directly to first base in this situation. Also note that there is no violation if the pitcher attempts a pickoff at second or third and throws to an infielder who is in front of or behind either of those bases (i.e., this violation is only in reference to pick-offs at first base).

First, neither a RH pitcher nor a LH pitcher needs to step off before throwing to first (or any other base).

In FED, this is likely a balk -- if the throw goes directly to F3 away from the base, then F3 must be close enough to the runner to be making a play.  That's unlikely if F3 is between F1 and 1B.

Here's a case play on it (no, I don't know why the font changes):

6.2.4 SITUATION J:

With R1 on first base and two outs, F1 attempts to pick off R1. As F1 pivots to throw, he realizes that F3 is not on the base, but is in his normal defensive position. F1 completes the throw without interruption. The coach of the offensive team wants a balk called on F1.

RULING: As long as F3 is in the proximity of the base, F1 would not be guilty of a balk. Proximity is umpire judgment and is based on whether the fielder is close enough to the base to legitimately make a play on the runner.

In OBR, if F3 was moving toward the base / runner before the throw, it's legal.  Otherwise, it's a balk.

Wait... Huh?

In no rule set is a pitcher required to step off the rubber to pick to first.  There are no separate rules for RH or LH pitchers.  They all apply to every pitcher.

The rule states that the pitcher must step directly to the base if he throws from the rubber, that is all.  The jump spin move from right handed pitchers is considered throwing from the rubber, and is legal in every level of baseball.

In the given example it is a balk if the throw is made from the rubber and the F3 is not in a position to make a play on the runner.  The pitcher could throw the ball to the base, even if F3 was not there and it would not be a balk.

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Here is one that I had never seen before.

High School fall game, runner on second.

RHP, looking at home, then "violently" lifts his back leg (right leg) and steps off the back of the rubber.

I use the term "violently" because he was simulating how he would lift his left leg if he was going home...it was that same quick motion up to where the knee was bent at a 90 degree angle.  

The intent was to obviously deceive the runner into thinking it was his front leg making that motion...but he simply stepped off the back of the rubber.

My son was hitting when he was doing this and said it was very confusing because from that straight angle (mound to home...and I presume also to 2nd) it actually looked like his front leg for an instant.  

It "seemed" like it should have been a balk, but I don't know if by rule it was since he was stepping off the back of the rubber when making that motion.  

If not a balk, then it is a good move I am surprised I have never seen anybody use before.  He obviously couldn't throw from that position...but if the runner broke into his secondary lead when he did that quick leg kick, he would easily be picked off.

Not a balk. Intent to deceive is irrelevant if there is otherwise no violation of the balk rules. I've actually taught this, but, in five or six tries, I've never seen it fool anyone. The only thing you might argue is that, after he lifts his foot off the rubber, the continuation of the leg up to simulate his motion is a balk because he is simulating the pitching motion while not on the rubber. However, I consider that argument a stretch...not that it would stop me from making it if one of my guys got caught on this.

Thank you.....In the game, no balk was called.  So I assume the judgement of the umpire that the first baseman was in proximity.  He clearly wasn't, the pitcher surprised the first baseman with the throw, he caught it, fans chirped a bit and the game went on.

To add to the above post, one important factor if someone decides to try this is to make sure the upper body doesn't balk. Bringing the hands in to the belly or lowering them as if you were going to come to the plate definitely IS a balk.