The best way to throw a nine-inning complete game these days is to just throw a no-hitter. “Just” isn’t a term that’s fair for an achievement that’s been done fewer than 300 times by a single individual in Major League history, of course. But the point here is to highlight a strong trend in MLB lately: We’re seeing the highest percentage of nine-inning complete games that are no-hitters on record.

• All-time no-hitters in MLB history

We’re specifying nine-inning (or longer) complete games here since an official no-hitter isn’t currently doable in a seven-inning game, as with Madison Bumgarner’s outstanding outing earlier this year. For the purposes of this story moving forward, any reference to a "complete game" will mean nine-plus innings, to avoid that repeated innings reminder. And all no-hitter totals for seasons refer solely to those accomplished by individuals, for a comparison of individual complete games and no-hitters.

Here’s some context on no-hitters and complete games in 2021.

Almost half of complete games have been hitless

So far in 2021, 42.9% of complete games have been no-hitters. That percentage had never been higher than 2% before 2007, when it was 3.53%. It has fluctuated since, but has not dropped below 1% since then, and has risen even more steeply in the last few seasons.

In 2015, there were seven no-hitters, tying the modern-era record, and we saw 8.75% of complete games net out to be those no-nos, with 80 total complete efforts. It dropped to 1.45% in 2016 before rising again, to 2.13% in 2017.

In 2018, 5.56% of complete games were no-hitters, and in 2019 it was 5.41%. Then in the shortened 2020 season, there were two no-hitters among just 14 complete games -- a rate of 14.29%. And that brings us to this year, at six of 14 thus far.

How does that compare to the distant past? Well, in 1901, 0.07% of complete games were no-hitters. The first season where the percentage was even 1.0% or higher was 1990 -- when it was 1.71%. Prior to 2021, there had been 21 seasons since 1901 where 1.0% or more of the complete games were no-hitters, and they all have been since ‘90.

Complete games on the decline

What exactly is happening here? Well, it’s no secret that the total number of complete-game outings by pitchers has been diminishing for a while. In 1901, when the American League began, expanding the total number of MLB teams, there were 1,369 such performances. In the Year of the Pitcher in 1968, there were 814. By 1988, there were 511 complete games, and by 1996, the first full season of the Wild Card Era, there were 240.

In 2007, there were fewer than 100 complete games for the first time, when there were just 85. The season-long totals jumped back into the triple digits in 2008-12, but dipped back to 95 in 2013 and have not risen above the 100 mark since.

9-Inning CGs, since 2013
2021: 14
2020: 14 (shortened season)
2019: 37
2018: 36
2017: 47
2016: 69
2015: 80
2014: 93
2013: 95

Over the course of that span traced above -- from 1901 to present day, we’ve gone from 16 total teams in ‘01 to 30 teams today. That means there would theoretically be more chances for complete games, not fewer, since there are more teams and more games.

We’re getting better-quality complete games as a result

But of course, pitching philosophies and trends are not exactly the same as they were in 1901. We know more about training, and it is important to note that many of those early-year complete games featured plenty of runs. It was more about having a pitcher on the mound than that pitcher earning the right to stay there due to few runs allowed -- as we would expect now.

Here’s how the standards for leaving a pitcher in have changed. No pitcher has thrown a complete game where he allowed five or more runs since Cliff Lee on July 10, 2010. In fact, that’s happened just five times between the start of the 2002 season and 2010.

In 1901, when there were 1,369 complete games? 453 of those involved the pitcher allowing at least five runs, the most such outings in any season since 1901. Bullpens didn’t exist in nearly the way that they do now, and the standards and concepts with respect to relief pitching were entirely different. Saves did not become an official stat until 1969, which provides a year-mark for when bullpens began to resemble what we see today -- but even that is a far newer concept.

The last time there were even 10 complete games in a season where a pitcher allowed five or more runs was 1988 -- which matches up very well with 1990 being the first year that 1% or more of complete games were no-hitters. That shift in quality and expectations when going the distance.

Putting it all together

The reason we are seeing a record-high percentage of complete games that are no-hitters is twofold. The decrease in overall complete-game efforts, as detailed above, is part of it. But the other obvious component here is the record no-hitter pace. We’ve already seen six this season, the most ever before June, and are just one shy of tying the modern-era record and two shy of tying the overall record from 1884. At this rate, if you're a starter and find yourself high-fiving your catcher after the final pitch of the ninth inning on the mound, chances are, you got there by keeping your opponent out of the hits column.