I know the headline is a little alarmist, but now that I have your attention, I’m here to let you know that not all of these struggles are cause for alarm.
In this article, I’ll take a look at a handful of starting pitchers who struggled to maintain their strong starts to the season, sorting by the biggest ERA increases from April to May amongst those with at least 25 innings pitched. Based on underlying numbers and vibes, I’ll bucket these starters into guys you should look to cut or trade and who to buy or hold.
And remember, try not to worry just because a guy shows up on this list! For the most part, to have a big gap in ERA between any two months, you need to have done pretty well during one of them.
For most of us, April results are not that much more meaningful than the results we get from our teams during the rest of the season. For those of you who play in Cutline leagues, all the power to ‘ya.
But in practice, April results can have a bit of an outsized impact on fantasy teams. For one, early season-ending injuries are of course more impactful than similar injuries that happen later, since you have more output to backfill.
And April hot starts can sometimes be parlayed into months of strong performance. That Week 1 streamer who turns into one of the stalwarts of your otherwise lackluster rotation or the top prospect who earned a last minute spot in the starting lineup out of Spring Training.
We all know these feel good stories. We all know the other side of that coin, too. The early draft pick who limps through April with an inflated ERA. Or who Tatis’s their way through the first nine weeks of the season without a home run.
In this article, I’ll look at the starting pitchers who have seen the biggest improvements between April and May, keeping things simple by sorting by ERA and K-BB% to trim the fat before getting into meatier analysis on some of the more intriguing arms.
Jeff Zimmerman’s son competed in the State Track Meet this weekend, so he only had time to cover the pitchers while I’ll cover the hitters.
In this article, I am helping Jeff Zimmerman cover the hitters using CBS’s and Yahoo’s ADD/DROP rates. Both sites have the option for daily and weekly waiver wire adds. CBS uses a weekly change while Yahoo looks at the last 24 hours. Yahoo is a great snapshot of right now, while CBS ensures hot targets from early in the week aren’t missed. I will start with hitters being added at CBS who started the week on less than 40% of rosters.
Staying true to the format, the players are ordered for redraft leagues by my rest-of-season preference, separating out catchers and prospects from the overall hitter pool.
If you want to get a hit, trying to square up the ball is a great place to start. But not all squared up hits are created equal. Squaring up your grounders and line drives will likely help your batting average, but won’t do much in the home run department. Squaring up your flyballs, especially at the ideal launch angle, should help get the ball out of the yard.
If you look at the surface level Savant lollipops, you will see a “Squared-Up%” metric, which is represented on FanGraphs by “SqUpCon%”. This describes a batted ball event where at least 80% of the possible exit velocity on a pitch was obtained, given the swing and pitch characteristics, which typically means a ball that was hit on the sweet spot of the bat, according to Statcast.
As explored by Fangraphs’ Davy Andrews, even before we look at the launch angle of a squared up ball, we should acknowledge that not all of these swings result in a ball that’s hit even remotely hard, because a ridiculously slow swing that hits the ball on the barrel can still technically be squared up by the Statcast definition. But for the most part, hitters are swinging relatively hard. And we have ways to see just how fast they swing and how often they unleash their fast swings now, thanks again to Statcast.
With all of this in mind, check out the Fangraphs Squared-Up Explorer. This tool helps you see how often a hitter is squaring up the ball at different launch angles, highlighting the ideal launch angle for home runs and visualizing a given hitter’s profile compared to league average.
Using this tool, you can compare a given hitter’s profile against other hitters and during different periods of time. You can compare Gunnar Henderson’s hot start in 2024 to his 2025 and to his start to this season, as I did last week.
Today, I’ll run through a few examples that demonstrate the possible ways to use the Squared-Up Explorer and try to show you that you can and should use this tool yourself as a starting point for analyzing hitters, whether it be struggling bats you may want to cut or hot streak hitters you’re looking for an excuse to believe in. For the hitters I look into, I’ll provide some recommendations, but really want to invite you to use this exceptionally user-friendly tool yourself.
Before I get into analyzing what I think may be a relatively broken hitter, I have something to admit. This admission may sound familiar to you. Especially if you are at all impulsive. Or love to trade.
A few weeks back, after trading Corey Seager for Dylan Cease in what felt like an absolute coup, I got a bit ahead of my skis. Without looking at a single Fangraphs or Baseball Savant page, I fired an offer into the ether. I dealt away Michael King, Cade Cavalli, and Bo Bichette for Gunnar Henderson, in what felt like a classic buy low-sell high, where Henderson represented the low and King the high.
The point of this article is not to discuss King’s less than rosy peripherals. Nor is it to shame me for dealing Bichette before he seemingly started heating up. It is, at least in part, a cautionary tale, though I’d say it’s a hopeful one.
It’s nearly the end of May. Roughly one third of the way through the regular season. Already, we’ve had our fair share of surprises. New main characters are scattered across your league, or all concentrated on the roster of a sure to be smug top seed.
Whether it’s the manager who added Davis Martin early or the one who was utterly convinced by Jordan Walker and his offseason with Driveline, they’re certainly sitting pretty so far.
For every one of those managers, there’s the one who missed out on Corey Seager in the draft, bought low on the veteran slugger, watched him go hitless in the seven games after trading for him, begged for him to hit the phantom IL, and then knowingly grimaced while moving him to the actual IL at the end of last week due to back tightness.
Some like it hot. And the A’s are certainly some. Since their move to West Sacramento, A’s hitters have finally been treated to a friendly home park. But that park is much friendlier when the weather warms up.
Mapping the A’s Bats by Month at Home (2025)
Month
HR
FB%
HR/FB
ISO
wRC+
Mar/April
16
36.7%
11.0%
.159
96
May
15
35.7%
11.5%
.151
118
June
14
35.5%
11.6%
.147
99
July
23
39.3%
20.2%
.241
116
August
20
36.0%
14.2%
.183
107
Sept/Oct
17
36.1%
16.2%
191
108
In this case, timing is a proxy for expected weather. Put simply, since we expect it to be hotter in the summer, especially in Sacramento, we expect offense to increase as the hitting environment becomes more favorable.
They make us feel like gods. Those pitchers who begin the season on the fringe of being rostered who you stream against a weak offense to begin the season, who then go on to give you five innings with a handful of strikeouts and a win.
In this throw away culture where newer is always better, it’s easy to lose sight of the essentials. And that’s especially true when “newer” means throwing three different fastballs over 97 mph or uncorking splitters that are hurled so fast they necessitate a new name.
That presents an opportunity. To zig where the market is zagging today is to not cast aside the command artists as flukes, but instead to let results come before the flashiest of underlying numbers. If the K-BB% isn’t convincing and the Stuff+ is lacking, there is still a path to success, and to surplus value via waiver wire adds and trades.
