Pitcher Spotlight: Zach Eflin Is Throwing Harder, So What?

I love when pitchers add velocity. “Did you hear? Alex Wood is now pumping 94mph!” analysts whisper on Twitter. Crowds gather, eyes piercing a pitcher throwing a fastball that pounds a catcher’s mitt behind a failed swing. The excitement is captivating and calls for everyone’s attention as hype trains leave stations in droves.

This is the fun in fantasy baseball and Zach Eflin is the latest pitcher to get the spotlight. After failed 2016 and 2017 seasons that were so ghastly I feel guilty sharing them with you (5.54 ERA and 6.16 ERA, respectively), Eflin has had a pair of successful starts to launch his 2018 campaign, holding an impressive 0.71 ERA, 0.79 WHIP, 27.7% K rate, and 6.4% BB rate in the minuscule 12.2 IP sample. The real story, though, is how he’s bumped his four-seamer’s velocity from the previous 93.5mph mark to 95.5mph this season:

Alright, Zach Eflin has increased his fastball velocity by two ticks. So what?

Adding velocity to your fastball is often correlated with success, but given the amount of failure Eflin has had in the past, even taking a step forward may not cross the threshold for value in 12-team leagues. I elected to watch both of Eflin’s games against the Marlins and Giants and wanted to break down the current status of his repertoire to help answer that question. Is the new harder throwing Zach Eflin worth our time?

For the sake of this piece, I focused mostly on the recent Giants outing as I think it was a greater representation of Eflin’s skill set, with a few exceptions. Let’s start with the man of the hour, his fastball.


I won’t beat around this because we all know the truth. Throwing harder is helping Eflin. It helps any pitcher. Let me give you three prime examples of swings-and-misses that probably would not have happened in previous years.

Here’s Pablo Sandoval badly missing on 96mph heat on the outside corner:

Evan Longoria failing to catch up to elevated 95mph heat:

And here’s Gregor Blanco falling over after failing to catch up to this heater right down the middle of the plate at 94mph:

I love that final GIF for multiple reasons, but comedy aside, the location is far from ideal. Eflin’s command of his fastballs in both outings was serviceable – nothing spectacular but good enough to get through innings without a torrent of hard contact – and I wouldn’t compare his feel for the pitch to the likes of Tyler Mahle or Michael Soroka, to name a few other young options. He didn’t showcase the ability to play inside and outside during at-bats and save for the above-average velocity, his fastball is a bit mediocre.

I think his fastball performed slightly better than what we should expect moving forward – it was the Marlins and a Giants team that floundered against hard four-seamers all week – but there is no denying that the added heat is helping him get away with a few more mistakes that he would otherwise. This sets a decent foundation for other offerings to come alive, but it’s not enough to steal the show like Soroka or even his teammate Vince Velasquez.


Here’s the most interesting pitch in Eflin’s repertoire. I am focusing mostly on the San Francisco game to show of Eflin’s arsenal, but his slider was a bit different in each game. In the first inning against Miami – the first frame he’s pitched in the bigs since 2017 – Eflin showed me something startling: a 91mph slider.

It looked a bit like a cutter, but it was a wild difference from his four-seamer and clearly a separate pitch. I didn’t expect to see a hard slider from Eflin and made me a bit excited. This could be a very solid offering to pair with 94-95mph heat, jamming left-handers and falling away from right-handers to earn outs on surprising late movement.

Later in the second inning, there was another slider, this time with loopier action and coming in just under 86mph:

Well this is interesting. Is Eflin intentionally featuring a split of cut-action and larger break sliders or is his execution of the pitch simply different each time he throws it? We’ve seen pitchers like Jakob Junis and Patrick Corbin purposefully change their slider velocities to confound batters, while we’ve also seen Fernando Romero and 2015 Luis Severino feature inconsistent velocity and movement with their sliders without intent.

I want to believe there is a mentality behind it as this can be effective. Hard sliders for weak outs and stealing strikes, while saving the heavier break as a weapon with two strikes.

There’s a problem: Eflin’s slider maxed out at 87.8mph and was a minimum 80.8mph in his start against the Giants. That’s a major difference. Let’s look at them from this Monday start.

First is a harder slider at 87.8mph:

Then the loopier one at 83mph:

Not as impressive, right? I can still see this combination being effective, but it doesn’t carry nearly the same upside when each offering is coming in 4mph slower. Yes, there was a small dip in fastball velocity from the first to the second start, but it was a 0.7 mph difference, not a whopping three ticks.

I’m not exactly sure what to expect out of it moving forward, but I’m inclined to believe the first start carried a bit more weight for Eflin given it was his first start of the season, making those harder sliders adrenaline-fueled and not something we should expect in the future. It’s too bad as the possible upside of increased velocity fails to stick without that beautiful 90mph tight slider.


The third option is a changeup that is far from polished. It lacks great fade or drop and will expose Eflin when his slider or fastball are failing on a given day. He throws it mostly to left-handers and even when he got a swing-and-miss, it felt as though the batter just missed it as opposed to getting wildly fooled:

There were times when it expressed above-average horizontal ride, but in those scenarios, it seemed like Eflin got on the side of the ball, causing him to lose his feel of the pitch, falling well out of the zone or easily poked for a hit:

This could develop with more time on the field and theoretically, the added fastball velocity could amplify the effect of this pitch on left-handers. It’s not out of the question, but there’s work to be done and that makes me concerned.


Eflin’s deuce is an infrequent fourth offering used to grab surprise strikes in the later innings. When it works, it has solid break and will get the desired result:

Or can shock for a two-strike pitch below the zone:

But in most cases, the pitch was wild and was a waste of a pitch from Eflin. Here he is narrowly avoiding a pair of HBPs during the San Francisco start:

I don’t see this curveball becoming a staple in Eflin’s repertoire, save for the possible rare outing where he gets a good feel and features it more heavily than his slider. I can fathom that scenario, but those will be far and few between.


Zach Eflin’s velocity bump is certainly going to make him a better pitcher in 2018 than in previous seasons, though beating his career numbers is far from a significant feat. With a fastball averaging over 95mph, he creates a decent foundation for secondary pitches to get a spotlight, though he hasn’t showcased the ability to feature heat on both sides of the plate within at-bats. His slider is a bit of an enigma, varying in both speed and movement between games. It could turn into his best offering rotating from hard cut action to a loopier whiff option, or it could settle in as a slightly above average breaking ball.

Eflin’s questionable third options will get exposed in future starts when there is a weak link in his fastball/slider combination, making it difficult to endorse Eflin as an add for 12-teamers. He has the ability to take advantage of weaker opponents – such as the Mets on Saturday – but he isn’t an arm I’d be racing to grab in standard leagues. Play the matchups while treating him as a streamer and don’t expect sustained success until we see refinement of his secondary pitches.

Nick Pollack is the founder of PitcherList.com and has written for Washington Post, Fantasy Pros, and CBS Sports. He can be found making an excessive amount of GIFs on twitter at @PitcherList.

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6 years ago

Great work as usual. I don’t think that 90+ slider is going to miss many bats – it hardly does anything – he is better off with the other one. Always nice to face the Marlins and Giants offenses! ZE is currently benefiting from a 100% strand rate and .200 BABIP accompanied by a 24% GB rate. It seems like PHI is good at producing guys like this – good enough to get your attention, but not good enough to hold it. If you are looking for a laugh, check out those K rates from past seasons – they are enough to make Jaimie Moyer blush. Gotta love a velocity spike.