In 2003, the Chicago Cubs won the National League Central largely because of the performances of their three young ace pitchers. Mark Prior, Kerry Wood, and Carlos Zambrano combined for a 2.93 ERA in 636 1/3 innings that year, and almost led the Cubs into the World Series.

Last year, the same three pitchers combined for only 468 1/3 innings, with a 3.36 ERA. Most of the quantity and the quality came from Zambrano – Prior and Wood pitched just 259 innings with a 3.86 ERA, and the Cubs finished three games behind the Houston Astros in the wild-card race. It’s fair to say that the injuries that caused Prior and Wood to miss a third of their starts also cost the Cubs a postseason berth.

Now, injuries look to threaten yet another Cubs campaign. Prior, 24, has been shut down indefinitely with inflammation around the ulnar nerve in his right elbow; Wood, 27, has not pitched since March 9 because of bursitis in his right shoulder and irritation around the rotator-cuff muscles. Both pitchers are scheduled to throw today, but it is unclear if they will be ready in time for the start of the regular season. Reasonably enough, people are wondering if that 2003 division title might have something to do with those injuries.

The numbers tell the story. In 2003, Wood, Prior, and Zambrano all ranked among the top eight pitchers in the National League in pitches thrown, alongside veteran innings eaters like Livan Hernandez and Russ Ortiz.

Prior’s ranking, in particular, raises eyebrows, given that he missed three weeks that year after a collision with Marcus Giles. He averaged 113.4 pitches per start, and threw at least 124 pitches in four of five starts down the stretch, including several in which the Cubs jumped out to an early lead.

If manager Dusty Baker drew any connection between the heavy workloads he demanded from his young starters and the injuries that wrecked last season, it didn’t show up in his handling of Zambrano, the youngest and perhaps the best of the three. Just 23 last season, Zambrano ranked seventh in the NL in pitches thrown, averaging 111.9 per game. For context, that was as many as the notoriously durable Hernandez, and a full eight more per game than Randy Johnson.

Many baseball commentators have argued that this is evidence of near-criminal irresponsibility on Baker’s part. Having at the least cost his team a playoff spot last year, and at worst crippled the career of Prior, one of the game’s most talented young pitchers, he proceeded to treat an even younger pitcher with equally reckless disregard.

I’ve made this argument myself. A mound of studies, some as many as 15 years old, purports to show that the overuse of young pitchers is the primary cause of avoidable injury. Young pitchers, the reasoning goes, should be kept to strict pitch-counts in an attempt to preserve their health.

But an equally interesting essay by the historian Bill James in last year’s “Neyer/James Guide To Pitchers” raised some serious questions about the premises of the earlier studies, and caused me to re-examine the idea that the best way to keep pitchers healthy is to keep them to low pitch counts.

The main implication of that line of reasoning is that pitching hurts pitchers, and that therefore pitchers should pitch less. While there’s a certain logic to that – if Mark Prior never threw a fastball, he’d probably never have any elbow problems – it ignores certain realities. Chief among them is that there’s no way to know which pitchers will suffer under heavy workloads. If Zambrano, for instance, was overworked the last two years, you’d be hard-pressed to prove it. His ERA last September was 1.01, and his fastball got noticeably faster about halfway through last season.

Some think that not discovering which pitchers can handle such a workload is an acceptable price for having healthier pitchers. If every pitcher were held to low pitch counts, the theory goes, we wouldn’t have any Woods, players whose development is stalled by repeated injury. But we also wouldn’t find out which pitchers are Zambranos, able to bear an unusual workload that gives them great value.

And there is another reality to consider, which is that there’s little, if any, proof of a correlation between high pitch counts and pitcher injuries. The evidence is suggestive, rather than definitive. It does make intuitive sense that heavy use would lead to injury – but it makes an equal amount of sense to suggest that the way to train a pitcher for the sort of heavy use expected of a frontline starter is to use him heavily.

And then there’s the most basic reality of all – pitchers just get hurt. They get hurt if they pitch and they get hurt if they don’t pitch; they get hurt under enlightened coaches and under coaches who tell them to rub some dirt on their arm and throw. Limiting their workloads isn’t necessarily a solution to this – as James suggests, perhaps the reason today’s pitchers get hurt more easily than in past eras is that they don’t pitch as much.

Last year, Wood and Prior averaged, respectively, 101 and 98 pitches per game, which no one could say is evidence of irresponsibility on Baker’s part. And yet, the two are injured while Zambrano looks strong as a bull. Milwaukee’s Ben Sheets ranked right with Prior, Wood, and Zambrano in pitches thrown in 2003, and last year he had a breakout season, ranking second in the NL in IP and third in ERA.

As it happens, I do think that Baker has made serious mistakes in handling his pitching staff. I’ve seen Prior and Wood left in to pitch when they were losing crispness and speed on their pitches and giving every sign of sheer exhaustion. There have been plenty of games that were well in hand, where they could have been rested, yet were not. In his third start of 2004, Wood threw 131 pitches. That was, at the least, imprudent.

But I can’t definitively say that anything Baker did led to his players’ injuries, or that they would have avoided injury had he done something different. I can say that his methods appear to have produced an absolute horse in Zambrano, while a more cautious approach might not have done so.

And for all anyone knows, he’s added years to the careers of Prior and Wood by pushing them to the limits of their endurance, the same way a coach will have a runner shave time off his mile by running so hard he breaks down, and then getting back up and doing it again.

Baker’s way isn’t the way I’d do it. It’s not the way many people would do it. That doesn’t make it wrong.