How has Jacob deGrom put together the lowest ERA (0.62) through a pitcher’s first nine starts since ERA became a thing? Well, one could point to his pinpoint command, his deep arsenal of pitches or his mental toughness.

But let’s not bury the lede here: deGrom is now the fastest-throwing starting pitcher tracked by modern technology, and that heat makes the whole pitching thing just a little bit easier.

It was less than a year ago when we pointed out that, at age 32, deGrom -- who will try to lower that ERA even further against the Padres in Friday’s MLB Network Showcase and MLB.TV Free Game of the Day -- was throwing harder than he ever had before. In fact, 2020 was the fourth straight season that deGrom had, somehow, increased his fastball velocity. This was not a normal thing.

Well, if you’ve followed baseball at all in 2021, you’ve likely noticed that deGrom is throwing even harder still. As in, "OK, I’m not entirely sure this is fair for Major League hitters" harder.

• The 3 ways deGrom has gotten even better

Let’s jump to deGrom’s most recent starts. He began Memorial Day in Arizona with 10 straight fastballs of 99.8 mph or faster, then finished off the first inning with a dastardly 93 mph slider to Eduardo Escobar. deGrom tallied two separate swinging strikeouts on 101-plus mph heaters that night, joining Justin Verlander as just the second starting pitcher in pitch-tracking history (stretching back to 2008) to pull off that feat.

How did deGrom follow that up on Saturday against the powerful Padres offense? Merely by firing in 33 different fastballs clocked at 100 mph or faster, setting the single-game, pitch-tracking era record for triple-digit volume -- ahead of two of the hardest-throwing relievers ever seen.

• Tracking deGrom's pursuit of history

Most 100+ mph pitches, single game, pitch-tracking era (since 2008)
Includes postseason
1) Jacob deGrom (NYM): 33, 6/5/2021
2) Jordan Hicks (STL): 29, 5/19/2019
3-T) Aroldis Chapman (NYY): 28, 10/8/2017
3-T) Nathan Eovaldi (NYY): 28, 8/19/2015
5) Jacob deGrom (NYM): 27, 5/31/2021

Are you starting to get a sense of how unprecedented this is? Consider this: deGrom’s last two starts were the first made by any pitcher since at least 2008 (and let’s be honest, probably ever) when that starter averaged triple digits on his fastball from start to finish. You know, like what premium relievers do for an inning … but stretched across six or seven frames.

Fastest single-game average fastball velocity, SP, pitch-tracking era
Min. 25 fastballs thrown (includes postseason)
1) Jacob deGrom (NYM): 100.4 mph, 6/5/2021
2) Jacob deGrom (NYM): 100.1 mph, 5/31/2021
3-T) Noah Syndergaard (NYM): 99.7 mph, 4/18/2016
3-T) Nathan Eovaldi (NYY): 99.7 mph, 8/19/2015
5-T) Noah Syndergaard (NYM): 99.5 mph, 6/27/2016
5-T) Noah Syndergaard (NYM): 99.5 mph, 6/15/2016
5-T) Andrew Cashner: 99.5 mph, 6/9/2012
Fastballs: four-seamers, two-seamers and sinkers

deGrom has created the “100 mph starter club” (membership: one), and it’s a feat made more remarkable by his age (he turns 33 next week), mileage (1,200-plus innings) and history with Tommy John surgery (way back in 2010). When we looked at deGrom’s heat surge last year, we identified a small handful of modern starting pitchers that, at similar ages, had also increased their fastball velocity year-to-year four straight times.

Now, of course, deGrom is making his fifth straight year-to-year jump. Per research by MLB.com’s Jason Bernard, J.A. Happ (2009-14) and Aníbal Sánchez (2008-13) are the only other two pitch-tracking-era starters who have matched that streak. Sánchez started adding velocity when he was young, and obviously neither he nor Happ was throwing anything like the heat deGrom is pumping in now.

Neither, really is anyone else: A starter averaging 99 mph fastballs well into June is ridiculous. It’s mind-boggling. It’s unprecedented: Even as pitchers across baseball have added more and more velocity in the last decade-plus, deGrom’s teammate, Syndergaard, is the only modern starter in the same top-end velo zip code.

deGrom, it's worth repeating once more, is about to turn 33. None of the other leaders on the chart were older than 26 when they topped their respective years.

Syndergaard’s story, of course, brings up an obvious question -- how long can deGrom keep this going? Is he on the verge of a blowout, or does his story of a mid-career starter creeping closer and closer to triple digits make him a singular case?

You could take the glass-half-empty perspective, or you could settle in Friday and enjoy history in realtime. No one’s really done what deGrom is doing and, somehow, it’s not clear yet where his ceiling really is.