Con: With so many young arms in Triple-A Memphis, their path toward making contributions in St. Louis becomes even murkier
If you want to play devil's advocate here, at what point will arms like Thompson, Graceffo, McGreevy, Rom, and Kloffenstein get real runs in St. Louis? What about guys like Tink Hence, Tekoah Roby, and Cooper Hjerpe who may not be too far behind?
One critique of the Cardinals over the last five or so years has been shoehorning young starters into bullpen roles, or never giving them much of a shot to start, and either stunting the potential as a starter (Ryan Helsley and Jordan Hicks come to mind) or letting them go and they find success elsewhere (Sandy Alcantara is the prime example of this).
Balancing having veterans you can rely on and real opportunities for young arms to shine is a tricky game to play. The Cardinals have not done this well in recent years, and while they must avoid the disaster of a rotation they've had this past year, they have to figure out a way to give real opportunities to these arms they say they are excited about.
While I understand the concern here, I would probably subscribe to the idea that first, opportunities will come, and two, if they have that kind of talent, they'll force their way into the conversation.
Injuries or underperformance will happen, and so rotation spots will open up. Even if not, I think we can undersell the value of developing at the big-league level in the bullpen. In 2013, the Cardinals had future starters like Carlos Martinez and Michael Wacha spend significant time in the bullpen, and they went on to become impact starters when the opportunities arose.
If any of those names truly have the talent to big real difference-makers in the Cardinals rotation, then they'll likely play themselves into that role at some point. There also is not a rush to get those guys into the rotation. Most of them, if needed, can hold off one more year from a rotation opportunity, and I wouldn't be worried about how it impacted their development.