The number of frontline starters who have lost a significant amount of fastball velocity compared to the first month-plus of last season is startling. This isn’t just a few stragglers. It’s a half-dozen of the game’s best pitchers and a handful more in the next tier. It’s Cy Young winners and superheroes and $200 million men and royalty.

No great unifying explanation seems to exist. Some are hard throwers who aren’t throwing as hard. Some have considerable mileage on their arms. Some are showing the vagaries of age. One, actually, is purposely not throwing as hard. Not all velo dips are the same, though all do raise eyebrows at a time when pitches zoom in faster than ever.

A year-over-year drop in April doesn’t necessarily portend doom. Pitchers can find their stuff in a snap. (See: Mat Latos, whose fastball averaged 91.4 mph in his last start after sitting at 89.3 mph for all of April.) The fear, of course, is that when fastball velo goes, it’s often for a permanent vacation. And while that, too, is far from a death sentence, it can force a pitcher to evolve on the fly, a task often fraught with peril.

The average April 2015-to-April 2016 velocity drop among starters with at least 20 innings in both years is about 0.3 mph – just as it was in 2013, 2014 and 2015, according to PITCHf/x data carried by FanGraphs and Brooks Baseball. Generally, when the April-over-April drop exceeds 1 mph, it’s worth at least asking questions. And considering …

1. Matt Harvey’s April velocity was down 1.3 mph from last season’s, those questions were starting to intensify. Then came his first start in May, which set off serious alarms. Last year, Harvey’s average fastball in April clocked in at 95.7 mph, the second hardest in the major leagues among starters. This April, it was 94.4 mph, still elite and 11th among his peers. Then came his May 3 outing against Atlanta, in which his average velocity was 92.8 mph. Now, that’s one start. Every pitcher is entitled a bad start, even one that would place his fastball velocity 30th among starters.

Because this is Matt Harvey, 92.8 mph is a screaming red flag and 30th among starters a blaring alarm bell, both of which induce questions like “Did he throw too many innings last year?” or “Is his elbow hurt again?” or “Does God hate the Mets?” And the answers to those, in order, are “Unclear,” “Unclear” and “Would’ve been yes but Bartolo Colon hit a home run Saturday and no spiteful deity would gift a fan base it hates with such glory.”

Harvey’s start on Sunday, then, had the sort of serious implications being assigned these days to a …

2. David Price outing in Boston. As expert as Mets fans are in the art of panic, Price is learning Boston can do a pretty good Chicken Little impersonation itself. Not only is Price getting shellacked to the tune of a 6.75 ERA, his fastball velocity is down 1.2 mph from last April, to 92 mph. Since his debut in 2009, Price consistently has been the hardest-throwing left-handed starter in the game. To see him not only cede that title but rank ninth among lefties – behind Steven Matz, Matt Moore, Robbie Ray, Chris Sale, Clayton Kershaw, Hector Santiago, Martin Perez and Francisco Liriano – is not exactly the sort of thing the Red Sox hoped for when they lavished a seven-year, $217 million deal on Price this offseason.

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On Sunday, he declared teammate Dustin Pedroia helped him identify a mechanical error that could account for the velocity dip. Price said an improper leg lift is jacking with the timing of his delivery and that “I’m not putting myself in my normal power position.” Some of his peripherals belie the idea that anything is wrong; Price’s 11.54 strikeouts per nine innings are about 33 percent higher than his career average, and his walk rate is right in line. At the same time, the average batted-ball speed against Price has been over 90 mph, a few miles higher than he desires.

If his velocity doesn’t come back – he finished last season at 94.2 mph, which showed a strong in-season gain – Price is good enough to adapt. Still, he’s only 30 years old, though that’s the same place …

3. Felix Hernandez finds himself, and his velo woes are far more acute than Price. In April, the King’s average fastball left his hand at 89.5 mph. It was not terribly regal.

Six miles per hour ago, Hernandez was a 20-year-old neophyte with more natural gas than Chesapeake Energy. Now, he’s doing an admirable job of staving off an ugly ERA despite a career-low strikeout rate and career-high walk rate. If either of those keep up, the ERA won’t stay friendly too long.

Hernandez has company in the 80s. James Shields’ last start, the one in which he allowed that home run to Colon? Sat at 89.8 a start after clocking 89.5. Adam Wainwright jumped to 90.7 in his first start this month after spending the entirety of April at 89.7 mph.

These are big names in the midst of big deals who illustrate the potential hazard of long-term pitching contracts. Three years and $79 million remain on Hernandez’s deal after this season, two years and $44 million on Shields’, and two years and $39 million on Wainwright’s. Each could adjust and understand the 80s, much like their counterpart in decade, demand you adapt to their odd ways. Rather than allow that moment to find him …

4. Chris Sale took it upon himself to drop his velocity this year. Last April, Sale was throwing 94.2 mph. Today, it’s 92.7 mph. And he’s loving it.

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In this age of velocity, Sale told Chicago reporters he doesn’t want to throw with maximum speed on every pitch. It was a glorious thing to hear, almost anachronistic and quaint. Toss a pitch … at 80 percent max velocity? Heresy! And yet here’s Sale, his ERA 1.79, his Fielding Independent Pitching metric almost exactly where it was last year when he was striking out 11.82 per nine innings but giving up too many home runs.

Sale, 27, has kept the ball in the park this season, and even with the diminished velocity prompting a diminished strikeout rate, that lack of homer happiness is making the transition to a more contact-oriented approach work. It’s a little more difficult when your velocity isn’t gifted to begin with, because then someone like …

5. Dallas Keuchel loses 1 mph and it seems like all hell is breaking loose around him. The Houston Astros have been terrible. Keuchel is walking nearly four batters per nine innings. And he’s in that ugly place having lost 1.2 mph on his fastball, same as Price and Corey Kluber, two of the three previous American League Cy Young winners before Keuchel in 2015.

When Keuchel arrived in 2012, he was walking more hitters than he struck out, giving up copious home runs and throwing 88. Two years sitting 89.5 mph, and he blossomed into a star. Back at 88 today, and not even a strong home run rate can save him from ending April at 87.9 mph.

Keuchel threw 248 innings last season, and the workload far exceeded his previous high. Some arms respond to those challenges. Some don’t. If the Astros contend this season, it will be because Keuchel turned his year around and didn’t suffer quite the drastic drop with which …

6. Gio Gonzalez is trying to figure out. Last April, the Washington Nationals’ – ahem – 30-year-old left-hander was throwing 92 mph. This season, he’s at 89.7 mph. For those who missed decimal week in school, that’s 2.3 mph, which is the difference between Noah Syndergaard and everyone else in the world not named Nate Eovaldi. It’s a huge drop, one that has come at the expense of Gonzalez’s strikeout rate but not his other peripherals.

And perhaps that’s where our understanding of velocity can improve. It’s great by itself, the greatest weapon a pitcher can have, and yet whatever it does to an ERA because of the spike it causes in strikeout rate can be caused by a similar improvement to walk rate or home run rate. It’s why you see so many players on the league leader ERA list and this leaderboard of the greatest velocity drops this April.

Gio Gonzalez -2.3

Kyle Hendricks -1.9

James Shields -1.8

Mike Pelfrey -1.6

Chris Sale -1.5

Madison Bumgarner -1.5

John Danks -1.4

Mat Latos -1.4

Felix Hernandez-1.3

Matt Harvey -1.3

On the opposite side of the chart sits …

7. Max Scherzer, Gonzalez’s teammate with the Nationals, Price’s peer in the $210 million club and the biggest name among the biggest gainers in April-over-April velocity.

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Scherzer is one of just five players to gain more than 1 mph on his fastball compared to the previous April’s. The other four: Matt Shoemaker (+2.3, though it’s not helping much as he was sent to the minor leagues), Michael Pineda (+1.9), Hector Santiago (+1.5, and more on him later) and Jonathon Niese (+1.3). That’s it.

Naturally, whereas so many of the starters throwing softer have had ERA renaissances, Scherzer’s sits at 4.60 because one-fifth of his fly balls are going for home runs, a miserable stretch of luck for anyone. Scherzer is great. Scherzer with any more velo is the hardest-throwing version yet, and for someone on the cusp of his 32nd birthday, it’s a testament to his great work ethic and dedication to the craft of pitching. That Scherzer sits over 94 and still is 5 mph behind …

8. Aroldis Chapman never will cease to amaze. Whatever the view of Chapman as a human being – and after the domestic incident this offseason, baseball’s is near-universally on the skeptical side – what he does as a pitcher is incomparable.

Chapman’s average fastball in 2014 was 100.3 mph. Last year, 99.5. As soon as Monday, when he is reinstated by Major League Baseball after serving his suspension for the incident, we’ll see how hard he’s throwing now and marvel as ever at the arm that once threw a baseball 105.1 mph. Those numbers still feel wrong to type.

Thankfully when Chapman was gone …

9. Noah Syndergaard filled the void, satisfied our need for speed, quelled the jonesing for some pure petrol. And never has a starting pitcher’s been so distilled as Noah Syndergaard’s. After setting a record for starting pitchers last season with a 97.1-mph average, Syndergaard is throwing nearly a mile per hour faster at 97.8 mph. He’s like Roger Banister and John Landy in one.

The harder Syndergaard throws, the more fearful baseball gets, because the very last thing it needs is another phenom with a scar on his elbow, and perhaps the likeliest thing to cause it among pitchers the 23-year-old Syndergaard’s age is extreme velocity. Just look at the 10 fastest April velocities after Syndergaard this year and who has had or needs Tommy John surgery:

Nathan Eovaldi: Yes

Garrett Richards: Yes

Jose Fernandez: Yes

Yordano Ventura: No

Danny Salazar: Yes

Aaron Sanchez: No

Stephen Strasburg: Yes

Gerrit Cole: No

Rubby De La Rosa: Yes

And …

10. Matt Harvey: Yes.

That’s what makes this all so scary. It’s Daniel Hudson and Brandon Beachy and Kris Medlen. It’s complications. It’s this arm of Harvey’s, so special, also just as fallible. It’s trying to find out what’s noise and what’s real, whether that one awful start against the Braves was just an anomaly or something that proved prescient.

The verdict on Sunday: Hold the panic, sort of. He wasn’t throwing 92 mph. He wasn’t sitting 97, either. This was about average Matt Harvey 2016, with more 94s and 95s than 96s and 97s, with his stuff across the board down a mile or two. He had 10 strikeouts, though, and if that’s what it takes to jump start Harvey, perhaps this all will have been much ado about nothing by the end of the season.

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Still, we’ll watch Harvey’s next start, just as we’ll watch Hector Santiago’s (after he dropped 2.9 mph from his April average to his first May outing) and Yordano Ventura’s (his 2.7-mph April-to-one-May-star dip, down to 92.1 mph). Ventura had scouts wondering whether he was trying to pull a Sale, seeing as he hit 97 mph a few times, though that’s not anything close to the 100 he pumped regularly during his rookie season.

It’s easy to get lost in these numbers, to assign too much meaning to them. Show Harvey’s velocity dip and it seems like he’s doomed. Study batted-ball exit velocities, see his is the lowest among all starters and you’d think he’s the game’s best pitcher. The truth is somewhere in between, and as we marvel at Syndergaard’s speed and wonder about Jacob deGrom and Matt Harvey’s, we’d be smart to remind ourselves that speed is but one component to an art that never fails to remind us we don’t know as much as we think we do.