New Cardinals prospect will put revamped player development group to the test

When the St. Louis Cardinals pulled off the Sonny Gray trade earlier this offseason, it immediately intrigued me because of the amount of money Chaim Bloom was willing to send to Boston in order to acquire two vastly different yet intriguing and controllable arms from the Red Sox.

Richard Fitts, who has already seen big league action, is more of that prototypical Cardinals starter with a high-floor, lower-ceiling outcome. I don't mean that as a critique; the Cardinals could use multiple cost-controlled arms in the vein of Fitts and Michael McGreevy to help stabilize their pitching long term. But Bloom and his staff have been diligent to target more upside in their stable of arms, and lefty Brandon Clarke, the other piece of the Sonny Gray trade, was a prime example of that.

Clarke, like top 2025 draft picks Liam Doyle and Tanner Franklin, majors on his "stuff" and, if he's able to harness it, has the ability to be an impact starting pitcher or high-leverage reliever in the future. That's something I think we all want the Cardinals to start betting on more often, as if they can continue to accumulate a bunch of those intriguing arms, they'll have better odds of developing front-line starting pitching.

Gray, although still a very effective starter in this league, is no longer a number one starter, and some debate whether he's even a number two at this point. So that, paired with his age and contract (even as the Cardinals ate a significant amount of it), means that a prospect like Clarke is going to have a few holes in his game — no smart organization is going to give away a surefire front-line starter for Gray at this point.

Still, Clarke clearly has the tools to be a steal for St. Louis, and I decided to do a deep dive into what likely caught the Cardinals' eye when it came to Clarke and what they'll need to optimize or improve in his game if he's going to reach his ceiling.

The "elite" in Brandon Clarke's profile:

1. Velocity

One trend that is hard to miss with Bloom's influence thus far is their desire to add guys with big fastballs to the organization. In today's game, velocity isn't everything, but it sure does matter, and the more velocity you have, the better of a chance you have of finding success on the mound.

Even back in high school, Clarke was touching 97 mph on the radar gun, catching scouts' eyes back then, and now has his fastball hitting 100 mph and living in the upper 90s. Baseball America had Clarke as a top 100 prospect during one of their midseason updates prior to his blister issues, and MLB Pipeline rose Clarke up to the Red Sox's fifth-ranked prospect, which is a big deal considering how strong their farm system is.

That velocity isn't limited to just his fastball, though, as his sweeper has some eye-popping metrics to it.

2. Sweeper

Clarke's sweeper is arguably the best pitch in the Cardinals organization right now. And that says a lot considering the kind of fastballs that Liam Doyle and Tanner Franklin have and the disgusting changeup that Luis Gastelum has in his arsenal.

Remember how I said Clarke has insane velocity? His sweeper sits in the 88-89 mph range and touches 91 mph. You know how crazy that is? Shane Smith was the only pitcher in Major League Baseball this year to average 88 mph on his sweeper. Cam Schlittler, the breakout rookie starter for the New York Yankees, averaged 87.9 mph on his sweeper, and it has helped him become a dynamic postseason starter already. That's the kind of velocity Clarke has on his sweeper.

On top of that, his sweeper averages 10 to 11 inches of sweeping movement, making it truly an elite pitch and potentially a "one of one" offering in Major League Baseball. Any time a pitcher has a pitch that is that good, it makes it far easier to find success. Clarke has his unhittable pitch in his sweeper, and he has a fastball that has the tools to be a dynamite second offering.

3. Elite extension

So, we already established that Clarke has top-end velocity and a sweeper that could very well become one of the best pitches in baseball. How about we add on the fact that he's a lanky, 6'4 starting pitcher with some of the best extension in baseball as well?

Extension measures how much closer a pitcher's release point is to home plate, and Clarke's 7.25 feet of extension would have put him in the 96th or 97th percentile of all pitchers in MLB this year.

Because of that, Clarke is able to see his plus-plus velocity play up even further because the perceived velocity is a few notches above what is already an elite speed, and the break on his off-speed pitches is even more deadly because hitters have even less time to react to it. Think about pitchers like Tyler Glasnow, Logan Gilbert, Jacob Misiorowski, Aroldis Chapman, Edwin Diaz, and Zack Wheeler. All of them have big-time velocity and spin, and paired with their elite extension, it makes facing them a tall task.

Obviously, Clarke has a lot of work to do to be mentioned in the same breath as those arms from an actual production standpoint, but the point is, he has the makeup to be that kind of arm. I promise we'll get to the areas he needs to improve in soon.

4. Eye-popping swing-and-miss

When Brandon Clarke has been on the mound, he's always missed bats, like a ton of bats. His 31 innings of professional baseball are obviously a very limited sample size, but he struck out 34.5% of the 174 batters he's faced thus far. That includes the stretch where he was dealing with a blister issue, which really hurt his ability on the mound.

Along with that, opposing hitters haven't been able to get hits off of him, posting just a .126 batting average against him in 2024. Yeah...that's pretty darn good.

So, why isn't Clarke a can't-miss top prospect then? Well, let's get into the areas he still needs to improve in, and there's reason to believe the Cardinals are the right organization to optimize at least a few of these issues.

Where the Cardinals need to help Brandon Clarke:

1. Changeup

Outside of his fastballs and sweeper, Clarke has two below-average secondary offerings in his changeup and curveball. Being able to develop a solid second breaking ball or off-speed offering will be crucial for his long-term development.

The reason I highlight the changeup here is because the Cardinals' new player development group has seen success reworking or introducing changeups with other pitching prospects in their system. I would have to imagine that Bloom and his staff believe they can help Clarke revamp or improve his current changeup, which would give him that crucial third pitch to be an impact starter. But as things currently stand, Clarke lacks that quality third offering.

2. Fastball shape

Even with his elite velocity and extension, Clarke's fastballs grade out with below-average shapes. Clarke throws a sinker and two-seam and four-seam fastballs, and the four-seamer in particular lacks the swing-and-miss you would think it could provide him due to the shape of the pitch. He can get away with that because of how dynamite his sweeper is, but if he wants to be an impact starter at the Major League level, he is going to have to continue to refine his heaters in order to match the hype it carries.

3. Command

Clarke showed issues with his command in 2025, and some of that can be linked to a blister issue he experienced during the year. (More on that later.) While he has had moments where he lands his fastball and sweeper in the zone with consistency, overall, his command issues need to be improved as he works in the Cardinals' system. Teaching command sounds so simple, but we all know that it can be a nagging issue throughout pitchers' careers.

4. Injuries

Injuries have already plagued Clarke early in his pitching career, even before he was drafted. Back in high school, Clarke had Tommy John surgery in 2019, and then he missed his freshman spring after undergoing surgery for thoracic outlet syndrome. Following that, Clarke transferred to State College of Florida and missed most of his first season there due to a stress fracture in his shoulder.

And then during Clarke's first year in the Red Sox's system, blister issues began to plague him just as he broke out on the mound and was receiving national recognition. While it is encouraging to see that he has not had any recurring elbow or shoulder issues since college to this point, he does already have a long and sketchy injury history to his name.

Brandon Clarke presents the Cardinals new player development staff with a huge test.

So as you can see, there is a lot to love about Clarke's profile, and if everything clicks, he could be a true impact starter with top of the rotation upside. But because of those issues I just named, there are a variety of ways things go wrong as well. He could become a big-time stuff starter who just can't be trusted as a front-end guy because of his inconsistencies. He could become a great bullpen arm but never be able to click as a starter. Or, frankly, injuries or inconsistency could keep him from ever being a big league arm.

But honestly, the Cardinals need more arms like this. Yes, some will flame out, but guys like Clarke, Doyle, Franklin, Tink Hence, and others give St. Louis a chance at developing true difference-making starters. And if they hit on a few of them, this rebuild truly accelerates.