Jack Flaherty is a cautionary tale for the St. Louis Cardinals

Long touted as the St. Louis Cardinals' budding ace, Jack Flaherty kicked down the door in the second half of 2019, seemingly announcing to the baseball world that he was going to be a dominant rotation anchor for the Cardinals over the next decade.

Flaherty's performance in his 15 second-half starts was scintillating: a 0.91 ERA, a 2.22 FIP, and an opposing batting average of .142. But over the next four seasons, injuries would take their toll on Flaherty, and despite flashes of his old self, he was never able to recapture that form with the Cardinals. Now, as he departs to pitch for the Baltimore Orioles, frustrated fans wonder what might have been if he could have remained healthy. 

But Flaherty’s saga in St. Louis is an important one to learn from, as it demonstrates that building a team around pitching is playing with fire.

Pitching performance is incredibly volatile. Pitchers who do well one year are much more likely than hitters to collapse the next year, and injuries are a big reason for that. Recall two of the Cardinals' previous can’t-miss aces-in-waiting: Carlos Martinez and Michael Wacha. They both had some solid years wearing the birds on the bat, but they were unable to consistently produce as No. 1 starters, partially because of health issues.

Teams should build around position players to be successful. While Jordan Walker is far from a sure thing for the Cardinals, it would be foolish to deal him for a top pitching prospect because of all that can go wrong with pitchers. Many teams prefer to develop position players from within and sign pitching on the free-agent market. That’s not to say that drafting and developing pitching should be avoided, but it’s a much tougher path to success when you're banking on pitching to form the bedrock of your future major league roster.

Flaherty was supposed to be a dynamite pitcher for years, but this sort of outcome is all too common for promising hurlers. As the Cardinals' front office works to get with the times in developing pitching for the modern game, perhaps the team will see more success in getting the most out of potential aces. But as Flaherty's Cardinals tenure showed, relying on pitching for the future is always a gamble.