It’s wise to be wary of Major League Baseball’s claims that it has arrived at a substantive new drugs policy. For many years it didn’t have one at all. Barry Bonds could have slathered himself with THG while in the batter’s box and been subject to no penalty whatever.

When the game finally did implement a steroids program two years ago, it was so ineptly designed that it seemed to tacitly allow, and perhaps encourage, the continued use of performance enhancing drugs.

While that history should inform any judgment of the policy announced yesterday by Commissioner Bud Selig and player’s union head Donald Fehr, one hopes that people won’t be so skeptical that they fail to realize this is a very good program, and an encouraging step towards eliminating performance enhancing drugs (PEDs) from the sport.

There are, of course, massive flaws in the program. First, while all the details on testing procedures and banned substances aren’t available at this writing, it’s most likely that the use of common PEDs like testosterone and human growth hormone will be explicitly permitted, as in the NFL. Because these are naturally produced by the body, there is either no way to test for them, or, at best, means to test for elevated levels, which a player may be naturally producing. Don’t expect players to go back to their lithe builds of the 1980s.

A second flaw is simply unavoidable. Chemistry is always ahead of enforcement. Baseball can only ban substances it knows about, and it can only penalize for substances it can detect.

There are, no doubt, more drugs out there like THG, the substance Barry Bonds used, supposedly unknowingly. The only reason anyone knows about THG is because an anonymous person sent a sample of it to an anti-doping group.

Masking agents will be banned under the new policy, which is the equivalent of passing a law making it illegal to commit an undetected crime. There’s not much baseball can do about this, but it’s another reason why players are unlikely to start shrinking any time soon.

A third flaw is the apparent lack of mandatory penalties. The much-trumpeted 10-day suspension is not actually the punishment for first-time offense, but the maximum allowable punishment, which is a very different thing. When presented with the positive test of a popular, iconic player, there will be great pressure on baseball to impose a quiet, private penalty.

Despite these flaws, this is nonetheless a good program. An important element of it is random, year-round, unannounced testing.

Part of the reason the previous program was such a joke was that players weren’t tested in the off-season. Furthermore, once a player had tested negative, he knew he wouldn’t be tested again. This made it possible for a player to merely cycle off whatever he was using, produce a clean test, and cycle back on. Under the new guidelines, that won’t be possible. Determined users will simply acquire substances for which there are no tests, but fear of random testing should keep many players clean.

Also important is the mere fact that MLB is banning a comprehensive list of substances. The fact that various drugs deemed illegal under international anti-doping protocols were technically permitted in baseball was an ongoing embarrassment to the sport.

Most importantly, though, this is a good-faith effort. It isn’t the most stringent program that could be conceived, but there is no mistaking this for another attempt to quiet critics while giving free reign to juiced-up cheats. And that’s what matters.

No reasonable person can expect any drug-testing regime, no matter how well designed, to eradicate PEDs from baseball. Total elimination of these drugs isn’t the standard the sport needs to meet to maintain its integrity and its credibility with the public.

But it does need to make a serious attempt, and a good beginning is by making it impossible for a player to simply inject common steroids with impunity. So long as both the players and management remain flexible, willing to change elements of the program that aren’t working, and committed to transparency, muscle-bound frauds will no longer embarrass the sport, but only themselves.