In case you haven't heard, home runs are up. Like, way up. But for Stephen Strasburg, homers are down.

Truth be told, everything is down for Strasburg this year, in a good way. But the thing that really sticks out is his improved ability to keep the ball in the park, especially in a season that's seen more taters than an Idaho farmers' convention. To fully grasp just how stingy the Nats' pitcher has been with the longball, consider his past four starts:

1. Aug. 24 at Houston: Facing a stacked Astros lineup that came into the game tied for the major-league lead in home runs, Strasburg gives up zero bombs.

2. Aug. 30 vs. Miami: A day after blue-hot Giancarlo Stanton went yard for the 18th time in the month (tying an MLB record for August), Strasburg tosses a complete game in which he keeps Stanton in the park all four times he faces him.

3. Sept. 5 at Miami: Despite homering twice in his previous three games (Nos. 51 and 52), Stanton -- who by the way has owned Strasburg over the course of his career -- goes without a homer against the Washington righty, as do the rest of the Marlins.

4. Sept. 10 vs. Philly: Strasburg holds Rhys Hoskins (and the Phillies) without a home run. It's the only contest during a six-game stretch in which Hoskins, the rookie phenom who has hit 18 homers in 36 games, fails to go deep.

On the year, in 156 ⅔ innings, Strasburg has given up just 13 homers, the best mark among National League starters and three fewer than anyone other than the Rangers' Andrew Cashner and the Tigers' Michael Fulmer. Sure, Strasburg missed four starts because of an elbow impingement, but even when we account for that and look at rates instead of absolute numbers, Strasburg still ranks No. 1 in the NL with a 2.1 percent home run rate that, if he's able to maintain it, would be the lowest of his career (not including 2010 and 2011, his first two seasons, when he made a combined 17 starts). That might not sound like a big deal, but given that home runs have become almost as common as fidget spinners, it's mammoth.

So, what's changed? He has cut back on the cheese.

For all the fuss over Strasburg's fastball -- when he exploded onto the scene in 2010, the former top overall pick averaged 98 mph with his heater, highest among all starters -- it's gotten him into trouble. Before this season, 68 of the 88 career homers that Strasburg had given up came on fastballs. That works out to 77 percent -- or 20 percent higher than the league norm (from 2010 to 2016, only 57 percent of all home runs came against gas). This year, that rate is exactly the same, as 10 of his 13 homers allowed have been on heaters (77 percent). The difference is, he's figured out that when it comes to fastballs, less is more.

Stephen Strasburg has front-loaded off-speed pitches during at-bats, lowering his overall fastball usage to a new career low. AP Photo/David Goldman

Coming into this season, Strasburg's lifetime fastball usage was 61 percent, well above league average. This year, his fastball use is a career-low 52 percent, right on par with the MLB norm. Instead, he's throwing more slow stuff, especially at the beginning of at-bats.

"He's been able to use his off-speed pitches early in the count to get strike one," catcher Matt Wieters said. "That keeps guys from gearing up on the fastball."

To Wieters' point, Strasburg is throwing first-pitch fastballs 53 percent of the time, down from his career mark of 70 percent entering this season. In related news, opponents have posted a .760 OPS against those first-pitch heaters, down from .922 over the first seven years of Strasburg's career. Not only is he throwing more off-speed stuff, he's throwing different off-speed stuff.

"He's going back to basics," pitching coach Mike Maddux said.

For Strasburg, that means dialing back the slider that he fell in love with last year (17 percent, up from 1 percent in 2015), and more prominently featuring a curveball that, thanks to improved command, has become a lethal weapon, limiting opposing hitters to a .156 average and a .230 slugging percentage.

"It's one of the best in the game if not the best," Wieters said of the pitch. "If you're not looking for it, you're going to have trouble driving it."

To understand just how much trouble hitters are having, it's helpful to look at HORP.

No clue what HORP is? You're not alone. That's because it's a stat that I recently created for a piece I did on Giancarlo Stanton. It stands for HOmer Rate Plus. (Full disclosure: I originally called it HaRP because "harp" is a real word with a nice ring to it, but folks questioned the presence of the "a," so going forward I'm using the more phonetically correct HORP.)

Not unlike OPS-plus or ERA-plus, HORP basically takes home run rates and adjusts them to account for the overall prevalence of bombs in any given year. As an example, let's use Clayton Kershaw, who's faced 609 batters this season and given up 20 homers. That works out to a rate of 3.3 percent, which just so happens to be on par with the league rate of 3.3 percent. So Kershaw's 2017 HORP would be 3.3 divided by 3.3, which works out to 1.0. In other words, by 2017 standards, Kershaw is a league-average server of home runs (crazy as that seems). Any pitcher whose HORP is less than 1.0 would be considered above average when it comes to limiting long balls; anyone who's more than 1.0 would be below average.

Now that we're all down with HORP, let's look at Strasburg's numbers (again, ignoring 2010 and 2011): YEAR BATTERS FACED HR HR RATE MLB HR RATE HORP 2012 653 15 2.30 2.68 0.86 2013 731 16 2.19 2.52 0.87 2014 868 23 2.65 2.28 1.16 2015 523 14 2.68 2.67 1.00 2016 598 15 2.51 3.04 0.83 2017 626 13 2.08 3.31 0.63

As you can see, Strasburg's 0.63 HORP this year is a career low, and by a bunch. Granted, he's in the midst of a 34-inning scoreless string that's made all his numbers look nice and shiny, but even before those past four starts, his HORP was 0.75, significantly down from the 0.91 lifetime HORP that he sported entering this season. And it'd be unfair to discount those past four starts anyway -- while it's possible that Strasburg's homer rates are down because of the scoreless streak, it's just as possible that his low homer rates are what's fueling the scoreless streak.

Regardless of how you look at it, the bottom line is that Strasburg's keeping the ball in the park better than anyone, and better than ever.