The publicly debated but privately agreed upon rule has been slow to develop despite all parties agreeing to its necessity. Olney reports that "the delay in getting the rules to teams ... has not been a reflection of uncertainty about whether the change would happen, but in determining the precise language for new rules."
What aren't up for debate are the core principles at the heart of the new rule: runners must have access to first base, and runners cannot "target" catchers. These principals were developed through the Playing Rules Committee, and included conversations with current major league players and managers.
While some have expressed concern about a rule that is put together in a slapdash manner, and the effects it could subsequently have on the fundamental aspects of the game, one would be hard-pressed to describe any changes baseball undertakes as "hasty." Whether that means the rule will be well written or not is another story, and therein lies the delay. MLB does not want a rule implemented that will raise more issues than it resolves.
"We've got to find out what the rule is and then we make our adjustments from there. It's something we've got to work on, so we need to know quick."
St. Louis Cardinals manager Mike Matheny was consulted by the rules committee, and he's on record as stating that the Cardinals are altering their mechanics to adjust to the impending change:
"We're probably going to show all of the plate, Give them somewhere to slide and then be in position to make the tag before they get there."
The idea there being to mimic how players receive throws on tag plays at second and third base, leaving the base unobstructed while attempting to apply the tag more quickly. The issue of course being that an errant throw can lead a catcher (or any other fielder for that matter) into the path of the runner, leading to a collision despite everyone's best intentions.
That's when it comes down to the umpires' interpretation and application of the yet to be finalized rule, which is all the more reason to implement the rule as quickly as possible. More spring training reps for catchers, runners, managers and umpires will do the entire sport a world of good.
Oh -- and if you were thinking that replay would play a part in all of this, it can be used to determine whether the runner was safe or out, but not whether the new rule was violated.