Maybe now he'll stop being cursed for using drugs he didn't use
As a baseball fan and an Angels paritsan, I am relieved to hear Gary Matthews, Jr. make that statement. This lets spring become about the possibilities of triumph instead of the inevitabilities of depositions. Let's play ball!
Now, back to the original question: What punishment is appropriate for performance-enhancing drugs?
Take the 'guarantee' out of contracts
"If you had a pill that would guarantee a pitcher twenty wins, but might take five years off his life, he'd take it." -- Jim Bouton, Ball Four (1971)
Anyone familiar with the words of Jim Bouton should not be too surprised by performance enhancers. We don't know if, when a favorite mid-century baseball player passes away, whether heavy use of greenies played a role. Speed could be creepier and harsher on the body than some of the steroids out there. No telling if the deadball era was because amped infielders of later generations got to the ball so much faster despite having not slept the entire roadtrip.
Since the temptation to try something that promises a three-hour high and whose consequences are "a long way away" arises in the average 15-year old, adding in the competitive will, the quest for glory and the chance to financially set one's family up for life will outweigh the negative unproven percentages of a distant future.
A few years back, I read that first baseman Wally Joyner admitted to having tried PEDs for a week in 1998 before flushing them away in remorse. A star at Brigham Young University, Joyner was the paragon of wholesomeness as a player for the then-California Angels in the 1980s. If we had lost Wally -- if even for a week -- we'd have lost the war.
The punishments for drugs in professional sports have been, historically, laughable. Pitcher Steve Howe had a half-dozen lifetime suspensions and died tragically last year at 48 with methamphetamine in his system. Marijuana is not currently banned at all. Want to make a libertarian baseball fan howl? Mention the bag of pot found by pitcher Darryl Kile's bedside when his body was discovered in a Chicago hotel.
Punshment considerations have to be in the context of how the offending player has negatively impacted the game's integrity. Does this affect a particular team's branding? Did this player take the job of someone else on the roster? The MLB Players Union is notoriously star-oriented and its advocacy of privacy privileges has cost many of its qualified members substantial salary as their jobs have been taken by their "union brothers" on the juice. The simplest punishment would be that players who are caught involved in banned substances and illegal drugs, be they recreational or performance enhancing, lose the right to have a guaranteed contract.