On Friday night, just a few days before the New England Patriots attempt to assume their rightful position as the class of the NFL (narrator: they did not), I was doing what any 28-year-old man does on a Friday night: talking about relief pitching. As I was scrolling Twitter, I ran into a tweet from Sammy James, a co-host of the Play Tessie Podcast. Sammy is always thinking outside the box when it comes to roster moves, and pitched old friend Jalen Beeks as a potential fit for the left-handed relief role in the bullpen.
He highlighted Beeks’ changeup, noting the remarkably low batting average and slugging percentage against it. If you look at those numbers and nothing else, it appears to be an elite pitch. I dug in a little bit further, and while I found that the pitch was solid, I wouldn’t place it among the league’s best changeups.
None of this is a knock on Sammy. He’s got great insights and has as many ideas on how to improve the roster as anyone. At the same time, I’ve written what feels like 1,500 pitcher evaluations, and don’t think I’ve ever broken down my methodology.
The Red Sox could use a left-handed reliever. Last season, Justin Wilson, Brennan Bernardino, and Chris Murphy were the first lefties out of the pen for the Red Sox. As it stands, none of those three is on the 40-man roster. Outside of Aroldis Chapman, there aren’t many left-handed relievers with major league experience on the team, making an addition to the group before the season begins likely.
There’s not necessarily a rush to acquire a reliever. While it’s definitely a hole, as teams cut down their rosters, there will be opportunities to find a lefty, and they won’t need much time to stretch out before the season. Still, having bodies in camp to see what you have is a good thing. So, with all that being said, let’s look at one option and see what he might bring to the table for Boston.
Jalen Beeks
The bulk of my analysis is done with three websites: Pitcher List, Baseball Savant, and FanGraphs. Baseball Savant is always a decent starting point, just for their dashboard information.
I focus on the left and right panels, although the middle panel is probably the most popular among people who pretend that they know what they’re talking about (that’s another rant for another day). On the left, we see the pitch usage chart, broken out by handedness. Handedness is everything. Garrett Crochet throws his sinker 16% of the time, which makes it appear to be a secondary offering. When we split it, we see it’s his most thrown pitch by a wide margin to lefties at 37%. For Beeks, we can see he’s a pretty fastball-heavy pitcher, using a changeup most often as a change of pace, and mixing in a cutter against lefties. On the right, I like to see the arm angle, because it provides some context about pitch usages. Beeks is more over the top, which means he’ll likely have a harder time generating East-West movement. The movement chart helps see how much of the plate a pitcher can cover, but it’s hard to draw conclusions from movement alone.
Pitching is about getting outs. The best way to get outs is to throw strikes. That’s what we look for next: what pitches does he throw for strikes, and how does he end at-bats? Beeks is a left-handed reliever, and while the three-batter minimum rule means he’ll have to get righties out as well, I’m mostly concerned with what he does in same-handed matchups.
Going over to Pitcher List, we can filter by handedness and see when Beeks is throwing each pitch.
The right side of the Counts tab is categorized into three sections: Early, Behind, and Two-Strike. Early consists of the first two pitches of an at-bat as well as 1-1 pitches, behind consists of 2-0, 2-1, 3-0, and 3-1 counts, and two-strike is any two-strike count (duh). If it were up to me, I’d have an additional view showing the percentage of each bucket by pitch type, but we can use Baseball Savant’s search function to find that. Beeks, for example, throws a four-seam fastball 58.3% of the time in “early” counts. Putting all of this together, it looks like he uses his four-seam fastball and cutter to get strikes, and his changeup to put hitters away.
Now that we understand what Beeks is trying to do, we can assess his effectiveness. The overview tab on Pitcher List is great for this.
Paring it down to one pitch, we get nice percentiles and averages, although sometimes I’m skeptical of how accurate the percentiles are (They’re based on total stats and don’t change based on the handedness filter, for example). Regardless, strike rate is always the first place I look, and Beeks fastball has a huge number. It also comes with a massive 60% zone rate, as well as a mediocre 9.5% swinging strike rate and 15.2% called strike rate. A 70% strike rate with swinging and called strike numbers that low likely means the ball is in play a lot. So how’s the contact?
Here’s where you might be tempted to look at batting average or slugging percentage, but those can lead you astray because they’re only considering the final pitch of an at-bat. A pitch that’s thrown only in two-strike counts out of the zone is going to have a low batting average, because it will result in strikeouts, weak contact, or be taken for a ball. I like to use Ideal Contact Rate (ICR) because the denominator is total batted ball events, removing strikeouts from the equation. For a fastball, we want to see a number below 40%. In Beeks’ case, the 53.5% mark against lefties is high. That’s in part because the pitch is in the zone so often, but also because the shape isn’t much of an outlier.
Beeks also throws the majority of his cutters early in counts, although 34% usage in two-strike counts is fairly high as well. A look at the metrics shows a 15.8% swinging strike rate and a 17.1% called strike rate. The strike rate is incredibly low at 51%, while the zone rate is also fairly low at 38%. Because it’s able to return both called strikes and swinging strikes, my assumption is he’s deploying it more as a slider in two-strike counts. Looking at the heatmaps (below) that appears to be the case. Further, if you look at the movements, he throws some cutters as hard as 88 mph with less vertical drop, while others are as slow as 82 mph.
The pitch returned a 44.4% ideal contact rate, which is high for an off-speed pitch that isn’t in the zone much. It didn’t induce many chases either. It was able to generate whiffs at a decent rate, but it was a pitch that lefties handled well for the most part. Overall, when looking at the pitches designed to be strike-getters, both are hit fairly hard, and only the four-seam returns consistent strikes.
We’ll circle back to the strike-getting pitches, but let’s jump ahead to the changeup. Same-handed changeups are controversial. Some people hate them, some people are fine with them. I think it depends on the changeup, but that’s a discussion for another day.
Beeks throws his changeup 26.6% of the time to lefites, most of which are in two-strike counts. He throws it primarily down and inside to lefties, which always gives me pause, but it appears to work for him. While it’s only in the zone 35% of the time, the 42% chase rate and 20% swinging strike rate are both excellent. The ICR rate was 0%, but the sample was incredibly small. It’s been a solid pitch throughout his career, though, so it’s safe to say that hitters will continue to struggle with it.
While his changeup is a good pitch, I’ll again caution against using plate appearance level stats such as batting average against as your barometer. Take Jojo Romero, for example. He throws his changeup 22.3% of the time, and opponents hit just .167 against it. At the same time, it was never in the zone and only returned a 14% swinging strike rate and 50% called strike rate. While the pitch wasn’t getting punished, it also wasn’t doing its job by generating whiffs; batters were just letting it go for a ball. A .167 batting average might make you think it’s one of the best changeups in baseball, but it’s wildly inefficient.
So now that we’ve looked at all three of his pitches against lefties, what I see is a pitcher with a good putaway pitch, but one who needs to find a way to get ahead in counts. While his four-seam returns strikes, it gets hit too hard for him to throw it 50% of the time. His 2025 cutter shows some promise in its swinging and called strike numbers, but it doesn’t get enough chase to support a 38% zone rate.
He was very successful against lefties in 2025, so there isn’t necessarily a need to make changes, but there’s room for improvement early in counts. I’m speculating at this point, but a return to his 2024 cutter, which featured more vertical lift and was slightly harder, could pay dividends. He used the pitch more often, and while it wasn’t returning strikes at a high rate, the contact against it was poor. High cutters can often drop back into the zone for called strikes, which would play well off his four-seam fastball. Again, Beeks was great against lefties in 2025, but the contact stats against his fastball suggest some regression there if he doesn’t make changes.
I’ve written 1,500 words about Jalen Beeks so far, so I won’t repeat the process, but you should. Use Pitcher List and Baseball Savant, and tell me what you think about Beeks against righties. It’s fun. I promise.
There’s one more part I haven’t mentioned, and it’s arguably the most important. Watch the pitcher pitch. While a huge swinging strike rate can’t be faked, you might see a pitcher who’s missing spots over and over again and posit that they won’t have the same success consistently. In the case of Beeks, you’ll find an unorthodox delivery that looks to be deceptive. It reminds me of Kutter Crawford, but the ball is hidden at his hip rather than his ear. Nerds (like myself) run baseball (not me), but the game is still played on the field. There’s a lot to learn by watching.
