You may have noticed that spring training is about to begin, yet baseball still has not banned home-plate collisions.

Both the players and owners want to enact such a rule to protect catchers, but the issue -- somewhat like expanded replay -- is more complicated than it appears.

As Hall of Fame manager Joe Torre, a member of the Playing Rules Committee, said last month, "We are writing a rule. It's not finished being written because it's not easy."

An agreement is still possible, perhaps even probable, considering the desire of both sides to make a deal. But the first spring-training games are two weeks away. As camps open, coaches should be teaching the new rules, and players should be practicing new techniques. But nothing has been decided.

The idea sounds simple: Eliminate malicious hits on defenseless catchers. But baseball, by requiring base-runners and catchers to stop reacting instinctively, might expose those players to a different risk of injury -- and also change the way game is fundamentally played.

If a catcher reverts to past behavior, blocks the plate and collides with a runner who is out by 10 feet, should the run be allowed to score? Under the strictest interpretation of a collision ban, the answer would be yes.

Players, in short, will need to be retrained – catchers in the way they receive throws, base-runners in the way they approach home plate. Baseball, rather than go too far with a new blanket policy, actually might want to consider some type of phase-in, banning vicious collisions immediately while allowing players to learn how to position themselves on less extreme plays.

Frankly, it's difficult to imagine how such a plan might work. But better to crawl before you walk, especially when too rapid a rollout could result in unintended consequences, creating new problems.

The issue, especially for the base-runner, is ambiguity; he needs to know how to approach the plate. Maybe the best path for baseball is to follow the NCAA, which enforces rules that encourage players to avoid collisions at all bases whenever possible.