Stephen Strasburg didn’t pitch the game of his life on Wednesday or anything, but he was plenty solid, allowing one run over six innings. He threw his fastball around the familiar 95. He threw his changeup around the familiar 88. He threw his curveball around the familiar 81. And then it seemed like there was something else. The Nationals broadcast on several occasions noted that it looked like Strasburg was throwing some kind of slider, at 89 – 90. He’s fiddled with the pitch before, but only infrequently. Strasburg himself? He later denied that he was up to anything.

Strasburg appeared to get Norris on a slider, which would be a new pitch in his arsenal that he seemed to mix in a few times throughout the night. After the game, however, Strasburg denied that he had added a slider. “No, same stuff I’ve been doing in Spring Training,” he said.

Now, that’s not the most firm denial. But it also just doesn’t matter much. Strasburg can say what he wants, but he can’t control what we see with PITCHf/x. And PITCHf/x picked up on something.

Time for a couple plots! First, a plot for Strasburg’s 2015 season. This shows pitch speed vs. spin axis, and as I said yesterday with regard to Aaron Sanchez, you don’t need to worry too much about what “spin axis” means, exactly. This is just a way of distinguishing between pitch types. So, last year’s repertoire:

Fastballs around the upper right. Changeups below them. Curveballs over on the left. That’s the Stephen Strasburg we knew. There are just a few pitches floating around the middle. Now, Strasburg’s start from Wednesday:

You see the fastballs, you see the changeups, and you see the curveballs. And there’s that fourth group, again in the middle. The best word we have for those is “slider.” The pitch fits the usual characteristics. Strasburg threw a dozen of them, out of 88 pitches.

It’s important to note that Strasburg has some prior experience with a slider. In fact, here’s an Adam Kilgore headline from May of 2014:

Stephen Strasburg shelves his slider

There have been a few starts and stops. Strasburg debuted the slider at the beginning of 2014. He didn’t throw it again that season after April 25. Then last year, Strasburg threw a few sliders between the end of April and the start of May. He promptly dropped it one more time. In a sense, then, this is the third time around. It’s not a new toy. It’s an old toy, a toy Strasburg didn’t like to play with very much.

But there was absolutely something different about how Strasburg attacked the Braves. Out of the sliders that Strasburg threw between 2014 and 2015, just one of them was thrown to a lefty. It was a pitch Strasburg wanted to use to get righties to chase. In Atlanta, Strasburg threw eight of his 12 sliders to lefties. And if you look at the video, Strasburg wasn’t trying to get those lefties to flail. He was using his slider more like a cutter.

This is a selection of five clips. Look at the targets, and look at the execution. Strasburg did throw a few sliders away to righties, as sliders are typically thrown, but this particular approach isn’t something Strasburg has shown before.

The targets: in above the knees, in above the knees, in above the knees, in above the knees, and in above the knees. They weren’t quite in on the hands, but Strasburg wasn’t trying to bury these sliders in the dirt, like, say, Tyson Ross. It’s like he was looking for weak, sawed-off contact. That’s what a cutter is used for. So, I don’t know, maybe we should think of this as a cutter instead. The difference between a slider and a cutter is blurry. And I don’t even care so much about the label; it’s more about the idea.

To throw this pitch a dozen times suggests confidence. It’s not like Strasburg is hurting for putaway pitches. And he used it when he was ahead, behind, and even. The fact that Strasburg has abandoned the slider before means he could abandon it again, but 11 of the 12 yesterday went for strikes, and the approach was tweaked. I’m going to borrow a plot from Brooks Baseball. This is why I like the pitch moving forward. Here’s how Strasburg pitched lefties through the end of last year:

That image is from the catcher’s perspective. Pitches mostly occupy three areas. The upper left belongs to fastballs. The lower left belongs to changeups. The lower right belongs to curves. There’s not a lot in the upper right. It’s mostly empty, but now Strasburg could have a pitch to put there reliably. He showed good command Wednesday, and if it were to keep up, then Strasburg would have four pitches going to four different places. Lefties would have to try to cover everything, and you just can’t do that as a hitter. To say nothing of the added element for righties facing Strasburg. Maybe they’ll see the pitch more, too. This simply opens up doors. If Strasburg is going to throw this slider or cutter, it’ll give him something he’s never had, and it should help him with lousy contact.

Many among you might figure Strasburg doesn’t need to add a pitch. He struck out 30% of hitters a year ago with the usual three, and he’s clearly had an elite-level arsenal. Why tinker? But, there’s always room for improvement, and there’s always reason to adjust on the fly to stay one step ahead. If Stephen Strasburg evolves, that makes it all the more difficult for hitters to try to keep up. And Strasburg is thinking about the rest of his career. Three pitches have served him well to this point. Perhaps from now on, he’d be better with four. I’m not going to argue.