My Breakout Pick for the 2025 Chicago Cubs Might Be Their Least-Discussed Starting Pitching Option

[Matthew Trueblood]

When we talk about what shapes the 2025 Cubs' starting rotation might take, there's one player we talk about far too infrequently. He should be higher on prospect lists already, and his stock could rise sharply this spring.

Image courtesy of © Mattie Neretin / USA TODAY NETWORK

After being a fifth-round pick in 2022 out of Texas Tech, Brandon Birdsell didn't officially make his debut in the Chicago Cubs farm system until 2023. Since doing so, though, he's done nothing but affirm the team's faith in him, and as they've counseled him on some ways to rebuild and adjust his repertoire, he's added polish. Birdsell has made 50 professional starts and pitched 243 innings, with a 3.41 ERA and solid strikeout (22.8%) and walk (6.2%) rates. He made 18 starts for High-A South Bend, then 20 for Double-A Tennessee (spanning 2023-24), and he took the ball 12 times for Triple-A Iowa to finish 2024.

Birdsell's best stats came in the highest league, despite the hitter-friendly strike zone and ballparks of the International League. He's showed flashes of brilliance, touching 97 miles per hour seven times and comfortably sitting 95 even as he set a new personal high for innings pitched in a season. The fastball has an unusual shape, one the Cubs have partially effected: Rather than focused on riding, rising action, it's more of a cut-ride pitch, boring in on left-handed batters more than they expect such a hard pitch to do. It's a right-handed answer to Justin Steele's similar (but slower) heater. Birdsell also has a cutterish slider and a hard curveball, with the former offering sitting in the upper 80s with good vertical separation from the fastball and the latter down in the low 80s, with even more depth. He even sprinkled in a changeup with good arm-side run while with Iowa, though he doesn't command that pitch especially well.

Think of the above graphic as being from the batter's perspective. Birdsell pitches from a fairly vanilla three-quarters slot, but uses a modestly deceptive short-arm delivery, so that fastball can be remarkably tough to distinguish from the slider and curve (shown above as a cutter and slider; I disagree with Brooks Baseball about their classifications in this case). Birdsell isn't yet especially consistent with his vertical release point, but he doesn't give away any of his offerings by changing his arm action or release point noticeably for one of them. 

I'm not here to tell you that Birdsell will run a 2.50 ERA and strike out 10 batters per game, or anything. For one thing, I'm not yet sold on the big-league utility of the changeup, and without that, he might need another pitch or a change in the relationship between speed and movement on that hard slider/cutter. A bit of a sweeper would be a good way to attack righties, but lefties could vex him if he doesn't corral the change, unless he can locate the heater to all quadrants and maintain enough velocity not to get hit hard when he uses the outer half with that pitch to set up the bigger breaking ball.

However, I think Birdsell has upside few have properly grasped, and is very close to realizing it. He could yet be trade bait this winter, but assuming he's still around, I wouldn't be at all surprised if he got the call to the Cubs before fellow 2022 Draft prize Cade Horton. Birdsell will turn 25 in March. He's built up naturally and nicely, in terms of workload, and he's already spent almost half a season in Triple A. I think he can be a mid-rotation starter almost right away—certainly by the second half of 2025, should injuries or poor performance force him to be called upon.

Birdsell's viability should give the Cubs extra confidence about trading any of Javier Assad, Jordan Wicks, Ben Brown, or Horton, if the right trade option is out there. Other teams are unlikely to value Birdsell the same way the Cubs (presumably) do, since they've got him throwing a set of pitch shapes that they love and several other teams hate. At least 10 other pitchers at various levels of the Cubs organization get more attention, but I think Birdsell could be the surprise impact guy for the coming season.

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[Jason Ross]

I was surprised at how much I liked Birdsell when I deep dove into him for the prospect rankings. I always kind of thought of him as a #5 guy who could stick, but I just couldn't find many flags in his game and came away with the idea that there's some juice to squeeze there. Glad I'm not alone!

[Bertz]

Probably a good place to post this

I think there's a decent chance he gets smacked around by big league lefties (I know he hasn't had issues to this point), but essentially everything else is there already.

One kind of weird thing is that ZiPS hates him.  For a guy who is a data darling I expected the opposite and to need to go "woah woah woah pump the brakes buddy" to the projections.  I am curious what the hell it sees that has it throwing up the red flag.

[Matthew Trueblood]

26 minutes ago, Bertz said:

Probably a good place to post this

I think there's a decent chance he gets smacked around by big league lefties (I know he hasn't had issues to this point), but essentially everything else is there already.

One kind of weird thing is that ZiPS hates him.  For a guy who is a data darling I expected the opposite and to need to go "woah woah woah pump the brakes buddy" to the projections.  I am curious what the hell it sees that has it throwing up the red flag.

PECOTA (111 DRA-, -0.1 WARP, 18.6% K, 34% GB) hates him, too, doesn't think he'll miss enough bats and that he'll give up too many fly balls. I think there's a case to be made that his pitch mix changes altered that even within this season, in a way the projections won't catch because of the noise created by older results info? But yeah. There's a chance I'm on an island here, or that me and Jason are, at least. Haha.

[Jason Ross]

6 minutes ago, Matthew Trueblood said:

PECOTA (111 DRA-, -0.1 WARP, 18.6% K, 34% GB) hates him, too, doesn't think he'll miss enough bats and that he'll give up too many fly balls. I think there's a case to be made that his pitch mix changes altered that even within this season, in a way the projections won't catch because of the noise created by older results info? But yeah. There's a chance I'm on an island here, or that me and Jason are, at least. Haha.

I do think the flyball thing is a bit of a concern. What I really liked was the chase% he had on the slider and that the fastball generated higher than league average in-zone whiff. It gives him a few different ways of missing bats - fastball in the zone, and the slider as a chase pitch. And as you pointed out - with the arm angle, allows him to hide the two a bit better (maybe why we see that data to begin with?). 

[Development DL]

Great supplemental data and insights . 

[Matthew Trueblood]

2 hours ago, 1908_Cubs said:

I do think the flyball thing is a bit of a concern. What I really liked was the chase% he had on the slider and that the fastball generated higher than league average in-zone whiff. It gives him a few different ways of missing bats - fastball in the zone, and the slider as a chase pitch. And as you pointed out - with the arm angle, allows him to hide the two a bit better (maybe why we see that data to begin with?). 

Do you have a strong opinion on how his pitches should be classified? I keep circling back to that, and I suspect not even he is sure right now, because the shapes and speeds have changed so much since he entered the org. There's even a fairly legit case for classifying his fastball as a cutter, which I guess would push the harder breaker to slider and the other to curve..? It's weird.

[Jason Ross]

59 minutes ago, Matthew Trueblood said:

Do you have a strong opinion on how his pitches should be classified? I keep circling back to that, and I suspect not even he is sure right now, because the shapes and speeds have changed so much since he entered the org. There's even a fairly legit case for classifying his fastball as a cutter, which I guess would push the harder breaker to slider and the other to curve..? It's weird.

I've really waffled. I think I sit in calling it both? I think he's got a fastball and a cutter he's been playing with. I'm just playing the eye test here, but here's a start from September 22nd - 

https://www.mlb.com/video/brandon-birdsell-s-stellar-seven-inning-start

The first strikeout? That's a fastball to me. That second strikeout? That looks like a cutter with how it look a bit like it dances down and out. Then he gets two K's on what looks like a fastball again...and then...hard sliders? Cutters? IDK, what those next two are. Then what is clearly a backdoor slider and seems much softer then those things I'm thinking is a cutter. 

There feels like a lot of iteration and shape play. Or maybe I'm just a terrible visual scout - there's always that!

[TruthisaPerson]

I snagged him in a couple dynasty leagues with deep minor league rosters. Cub fans know who he is, but many don't. 

[ryanrc]

This is a very interesting point and interesting topic. 
Birdsell has a #2 slot potential by 2027, but as long as he's a 3- pitch guy, I see him as a #4 slot guy. His rapid development surprised many people, me included.

I have him slated as a competitor for the crowded 2026 rotation, and an injury sub for 2025. I'm guessing he gets 2-4 starts in 2025. Maybe he makes a post-season roster as a long reliever, if he is fantastic right away. 

We have so much pitching depth right now, its wild to see fans or press be so negative about our pitching trajectory.

Also: why has everyone forgotten about Keegan Thompson? Now that the injuries are behind him, he could easily throw a sub 4 ERA season as a starter. I expected some team to trade form him as a starter by now - he'd immediately improve the White Sox rotation!