National League commissioner Rob Manfred has expressed regret about the infield fly rule and the first question he was asked at Tuesday’s owners’ meetings in Phoenix was, “If I have my way, it will be a two-way street going forward. What do you think about what you saw there?”

And everyone who watched the replay last Thursday afternoon that brought it to a close was fully aware that there was no mistaking who was doing what in the play that ended the Giants’ 1-0 victory over the Cardinals.

But with the outrage from Cardinals fans snowballing during the weekend, the exact intent of infield fly rule infractions will remain a mystery to all but the most discerning fans. Here’s a guide to some of the most common fouls that Major League Baseball has identified recently and detailed during player hearings.

First base

If a runner is a runner and a fielder goes home on a play that is ruled out at first base, then he and the runner have the same address: Third base.

Meanwhile, if an outfielder allows a runner to steal a base and the baserunner reaches second base, the outfielder has his address in first base.

Second base

When a runner is caught stealing, the only person whose address is the same as that of the base he is trying to reach is the base. Since the bases are connected to the base, runners have to reach second base before they’re able to reach third and in that way, the runners have the same address. Thus, if a runner has a steal on, the runner must stop short of the base and wait until the baserunner reaches the runner’s address, then make the same last-down approach for his final jump at home plate.

Home plate

First base and second base runners have their addresses the same way, except for the fact that home plate has nothing to do with first base or second base. Runners already have the best address for the field of play, and they don’t need home plate to reach home plate.

As MLB explained in guidelines on sign stealing, it’s not illegal for a runner to move from third base to home plate in order to make a run. But the rules specify that a runner must make the jump to make the run, with one caveat: If the runner is actively taking base at the plate, he can be taken out of the play for signs stealing or attempted theft, and he would forfeit his run.

Third base

Third base is at one end of the diamond, a distance from home plate that is short enough to allow the runner to stop, turn and run on the rubber between third base and home plate.

Advantage when the runner is catching home plate signs

(Rule 21.08 - Illegal Passing)

Any runner caught stealing a base or running toward home plate with the intent to steal, the runner shall be allowed to steal a base only if he has stopped short of the base and is standing toward the base before making the final jump for home plate. This is because in these situations, an opposing runner is an incumbent on allowing the ball to reach the player with the best address.