We could have done without commissioner Bud Selig’s self-serving plug on behalf of Jason Giambi and his charitable work.

Considering that George Steinbrenner is paying the Yankee slugger $23 million this season for what amounts to a part-time job – injuries have limited Giambi to less than half of New York’s games – giving something back is not just the right thing do, it’s practically an obligation.

That said, Selig made the right call Thursday letting Giambi off with time served and the sting of public scorn for what was, after all, a nearly four-year-old admission that he used performance-enhancing drugs. Giambi owned up to that during a federal grand jury appearance in the BALCO investigation in the winter of 2003, then apologized publicly – sort of, anyway – a little more than a year later.

We don’t know how much he said to Selig’s hand-picked steroids investigator, former Sen. George Mitchell, during their recent meeting. But with the commissioner’s threat of further discipline hanging over Giambi’s head, his cooperation apparently was enough – once Selig factored in the big lug’s charitable instincts.

Whether it’s a smart decision won’t be known unless or until more users agree to come forward and share what they know about the game’s supersized era. The message has been getting out for nearly a half-dozen years now, and the best guess on the number of juicers might still be the 50 percent figure Jose Canseco parlayed into a best-seller.

Punishment isn’t the goal of Mitchell’s open-ended investigation, nor should it be. Otherwise, Mitchell would be going after the cheaters who were already caught, like Rafael Palmeiro, or Mark McGwire and Sammy Sosa, who raised more questions than answers during an appearance before a senate committee.

For the moment, let’s leave the question of determining appropriate penalties to them.

The rest of us already are resigned to the fact that the last 15 years of baseball have been juiced. What we want to know, more than how many ballplayers should be punished, is how many were juiced.

Baseball always is touting its tradition and ties to the past, how the chance to compare the pitchers and hitters from different eras links one generation to the next. But as the ambivalence over Barry Bonds’ home-run trots makes increasingly clear, most of us regard that century-old tie to the past as hanging now by a few slender threads. If the Mitchell commission collects enough evidence to provide some context, we can make our own decisions on whether it’s worth mending.

The problem right now is that Giambi is the only ballplayer who’s been compelled to unburden himself. By taking any further punishment off the table, Selig might be able to coax other players to do the same. It’s the only reason to give Mitchell more time to complete a thankless job.

Skeptics never expected that the former senator’s investigation would amount to much. Selig has ordered club executives and general managers and perhaps even a few owners to talk to Mitchell, but the guess here is that most of them said they had plenty of suspicions, but no proof. If that’s all that Mitchell concludes, then Selig, too, can plausibly deny that he knew there was a problem.

What we do know is that during this era, everybody in the game was focused on squeezing every last dollar out of the game. The long ball was like a gift from heaven after the disenchantment shown by the strike and canceled 1994 season. Ballplayers, front-office people and owners did everything within the rules to keep them flying into the seats.

Most of the new ballparks that were built since then had short home-run porches and several owners sought, and received, exemptions from Selig to make them shorter still. The salary scale for middle-infielders who hit home runs was as bulked-up as the players themselves.

Here’s hoping that Giambi wasn’t the only one who took something out of his salary and gave it to a charity or two. Or that he’s the only one willing to sit down with Mitchell and spill the beans about some of what he knows.

It hardly seems like too much to ask, especially now that the commissioner is in such a charitable mood.