A look at starting pitchers who make their MLB debut at age 25 or above

It’s my opinion that a player’s age is an extremely important factor to consider when evaluating prospects. And most people do this on the young side while not necessarily applying it with as much vigor on the old side. We all get excited when a teenager performs well in Double-A. But some get excited about a prospect who’s old enough to rent a car and puts up some good numbers in the minors. And my take is that’s a train that you need to get off from as soon as possible.

There’s a lot of buzz right now about Christian Scott, who put up very strong numbers last year in Hi-A and Double-A. Part of the hype is about the numbers he posted, while the excitement also is a result of the relative lack of pitching prospects the Mets have in their system. Those two factors have Scott placed high on the various prospect lists published so far, including a fifth-placed ranking by Baseball Prospectus.

David Groveman recently did a look at Scott and cautioned us on reading too much into Scott’s 2023 season. David’s reasoning seemed to center on a results-versus-scouting take. I agreed with his conclusion, adding a bit about age into the conversation. My post elicited this response from NYM6986:

You have to hope that a pitcher drafted out of college will progress more quickly than a high school pick based on playing against better competition, and those playing their college ball in the Sunshine state get lots of playing time. Given that the average MLB career is about 6 years, being 25 does not preclude him from a nice average length career. Given the state of the starting rotation, it will be interesting to see which pitching prospects step up and stake their claim to a roster spot. Vasil making the leap in the next year would be great as well.

Any article or comment that makes us think is a good one. And that’s what this one from Steven did for me. I reached out to him before publishing this, to make sure he was okay with it. And he signed off on the idea.

The first thing that jumped out to me was the idea of the length of the average MLB career. It didn’t seem right to me. But there is an unattributed online source that puts the average MLB career at 5.6 years — https://mlbrun.com/average-career-length-of-mlb

With all of the people who come up for cups of coffee in one or two seasons, that number doesn’t feel right to me. But let’s say that it’s true. My opinion is that you can’t take a broad-based number like this and apply it to everyone. Especially not to starting pitchers who make their MLB debut at age 25 or older.

According to FanGraphs, there were 75 starters who were age 25 or older in their rookie season between the years of 2008-2012. You can see the full list here:

https://www.fangraphs.com/leaders/major-league?pos=all&lg=all&qual=y&type=8&ind=3&age=25&age=56&startdate=&enddate=&pageitems=200&month=0&stats=sta&season1=2008&season=2012

The time period was chosen to be somewhat close to our current season but still far enough away that we could see guys have a 10-year or more career. However, we don’t really have 75 seasons. There were 17 pitchers who made their MLB debut before their age-25 season, so as Scott didn’t accomplish that, those pitchers were removed. And there were seven pitchers from the Far East who didn’t pitch in MLB until age 25 or later not because they weren’t capable, rather they didn’t get the chance. Those pitchers were removed, too. Finally, Daniel McCutchen was on that FanGraphs list twice, so he was only used once.

That gives us a sample of 50 pitchers who are in a similar boat to Scott. The first pass at looking how long these pitchers lasted in MLB was to give them a full year, regardless of how much they pitched. Jorge Campillo was credited with five years in the majors with this requirement. But in those five years, twice he pitched five games, once he pitched two games and once, he appeared in just a single game. Understanding that, here’s how our 50-player sample worked out:

Fewer than five years – 20
Five years – 11
More than five years – 19

Additionally, this FanGraphs list of starting pitchers had 21 that had more than twice as many relief appearances than starts in their career, including 17 that had three times as many appearances as a reliever than they did as a starter. Craig Stammen appeared in 562 games and had 43 starts. This is not necessarily a bad thing. It’s a need for the Mets’ system to have minor league starters become major league relievers. It would be wonderful for Scott to become the next Stammen.

But, if we’re expecting Scott at age 25 or later to become an MLB pitcher with at least as many starts as relief appearances, only 29 pitchers accomplished this in our five-year sample. So, let’s look at these 29 pitchers and use a more vigorous standard for a year. We’ll consider a year as 15 starts or 30 relief appearance or 20 combined. Any seasons that fail to reach a year under this definition will be combined.

In the earlier example of Campillo, his four partial years totaled 13 games and one start – not enough to count for a year. Because we’ll have partial years, we’ll use “fewer than,” instead of a full year. So, in Campillo’s case, he would go down as fewer than two years. Here’s our list of 29 starters:

Player	<1	<2	<3	<4	<5	<6	<7	<8	<9	<10	<11
Randy Wells				1
Tommy Milone											1
Jeff Niemann				1
Mike Fiers								1
Lucas Harrell					1
Nick Blackburn						1
Armando Galarraga				1
Jorge Campillo		1
Jeremy Hefner			1
Garrett Mock			1
Miguel González							1
Corey Kluber										1
Josh Tomlin										1
Matt Palmer			1
Scott Richmond		1
Cole De Vries		1
Felipe Paulino					1
Dillon Gee							1
Andrew Werner	1
Virgil Vasquez	1
Doug Fister											1
Luis Atilano		1
Chris Waters	1
Dylan Axelrod			1
Henry Sosa	1
Tyler Cloyd		1
J.D. Martin		1
Samuel Deduno						1
Josh Geer		1
Totals	4	7	4	3	2	2	2	1		2	2

We see that 20 of our 29 pitchers had a career of fewer than five years. Furthermore, this is not exactly an impressive list of pitchers. Essentially, it’s Kluber and the 28 dwarfs. Sure, we’d be very happy if Scott turned into Fiers, Fister or Tomlin. But to me, this is the 99th-percentile result and our expectations should be considerably lower.

The one thing we need to keep in mind is that looking at MLB pitchers to make their MLB debut at age 25 or later includes a survivor bias. Scott has 12 games at Double-A under his belt. Those 12 were very good. But there’s no guarantee he even reaches the majors, much less pitches well and pitches for a long time.

Scott will be included in my top 50 list, which will come out before the end of the month. But he won’t be in the top tier, which are players where it would be a disappointment if they didn’t make the majors or serve as a valuable trade piece. Without a doubt, my hope is that he turns into a Stammen or a Fiers.

But let’s see him succeed in Syracuse before we get our expectations up too high.