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Kyle Hendricks knows he’s struggled the last two seasons. He knows he hasn’t looked like “The Professor” that Cubs fans grew accustomed to seeing every five days. He knows that, though he’s had plenty of success in the past, the game catches up to you and you have to be willing to adjust.

“You always have to keep evolving and keep adapting,” Hendricks said.

The saying goes that you can’t teach an old dog new tricks, but that doesn’t work in baseball.

As the game evolves, pitchers who refuse to evolve with it will get left behind. There are plenty of examples of starting pitchers who’ve adjusted their games to extend their careers, whether those adjustments come in their mechanics, their grips or just mixing up their pitch arsenals in general.

And Hendricks might be on the cusp of doing just that.

In a conversation with CHGO this week, Hendricks detailed the thought process behind adding a new pitch to his arsenal: a slider.

“It’s something I’ve thought about, probably, for a couple years,” Hendricks said. “You see where the game is, where it’s going and the pitches that are working. … We’ve thought about it. We’ve talked about it as a group. We’ve messed around a little bit with it, here and there. It’s tough to find when to incorporate something. I think it will, probably, be somewhere in the future for me at some point. I don’t know when that’s going to be.”

It won’t come tomorrow, it probably won’t come in a month, it might not even come at all this season, but it appears that a slider could be added to Hendricks’ repertoire at some point in the future. While “The Professor” goes back to the lab to experiment with it, let’s take a look at how we got here.

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First, it’s important to consider why Hendricks would be a candidate to throw a slider in the first place.

When pitching coach Tommy Hottovy was asked about the potential a Hendricks’ slider could have, he said Hendricks could develop a decent slider based on the way he throws his curveball. And in fact, the other parties in this conversation the Cubs are having agree.

“You look at what the wrist does, how the elbow unwinds. Basically just the throwing-arm portion of the throwing motion, he’s got very good characteristics of how that arm unwinds to be able to spin a breaking ball,” assistant pitching coach Daniel Moskos told CHGO. “You see that with the spin rates on the curveball. He’s able to generate a very elite-level spin threshold on the curveball, so I don’t see any reason why that wouldn’t be the case with a slider as well.”

Indeed, Hendricks’ curveball spin rate is elite, as it lands in the 90th percentile (figure below).

Hendricks said his release point does indicate that he could develop an effective slider, and he even suggested that his mechanics might be even more suitable for throwing it as his primary breaking pitch.

“Just where my arm slot is, a slider would probably be more natural out of that slot,” Hendricks said. “Trying to throw a 12-6 curveball, it’s hard sometimes to get that far on top of the ball and get out front and spin it really hard still. So yeah, I think my pitch type and everything else would lend itself more to a slider, and then just find spots to use my curveball like I do now. Or I don’t know, if you end up just bagging it completely at one point.”

That brings to mind similarities with another starting pitcher, the one Hendricks outdueled to win the National League Championship Series in 2016: Clayton Kershaw.

Both Hendricks and Kershaw’s curveballs are thrown with 12-6 action and the same, extreme vertical release point of about 6.4 feet, which is taller than 83 percent of Major League Baseball (figure below).

Kershaw, with his extreme vertical release point, now has a sweeping slider which has generated more horizontal break than 62 percent of lefties this season and nearly doubled his slider usage from his early career rate. In 2008, Kershaw threw a grand total of seven sliders. The first time Kershaw threw sliders on at least 30 percent of his pitches was 2016, when he used it 33.4 percent of the time. By 2021, it was his most-thrown pitch, and this season, the southpaw has thrown a slider on 44.2 percent of his pitches.

Not that a Hendricks-to-Kershaw comparison works every time, but in this instance, could Hendricks follow a similar path if he does indeed incorporate that slider?

“I could see that being a thing,” Moskos said. “I would say that Kershaw added this a while back. It was more of a cutter back then, and now has trended to a little bit more of a sweeping slider as he’s just kind of evolved from who he was to who he is. We’ll see where we get to with (Hendricks’) breaking ball.”

The pitch data and the precedent set by a future Hall of Famer with a similar arm slot show that there’s potential for success in Hendricks adding a slider to his repertoire. Plus, having a teacher like Moskos, who’s had plenty of success helping other arms develop the pitch, doesn’t hurt.

“You’ve got to have the right people that you’re talking to,” Hendricks said. “Somebody that has that much experience, been around so many guys, some of the new-school minds in that realm, but also has worked with a lot of guys, a lot of pitchers, and had success with it. Those are the guys you want to pick their brains.”

The question now becomes when the addition of the slider might actually happen.

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Over his last three starts, Keegan Thompson has started showcasing a shiny, new weapon of his own.

A slider of that sort wasn’t in Thompson’s arsenal in the past, but when he was inserted into the rotation a few weeks back, he got the chance to tinker with it between outings. The five-day starter routine of side-sessions permitted time for Thompson and the pitching coaches to work on the pitch. As a result, over his last three starts, his slider has made up nearly 10 percent of his repertoire.

“The funny thing is, people are only now starting to catch on to the fact that Keegan is throwing a slider,” Moskos said. “That process started before. It’s been the same process ever since he started taking turns in the rotation. We’ve got the in-between side to be able to start working on things, and so now, that’s time to say, ‘OK, let’s jump on this.'”

Of Thompson’s last 10 outings, nine have come as a starter, including his last seven straight. And with that set routine in the rotation, he’s had the time that he didn’t have as a bullpen arm to work on the pitch.

“He’s had that many opportunities to start working on the slider,” Moskos said. “He’s only been throwing it for the last three games now, really. It took a five-start window to be able to develop the confidence in it.”

That last part of Moskos’ quote is the key. Not only do pitchers and pitching coaches have to work on maintaining the grip, the shape and everything else that goes into throwing a pitch, but they also have to make sure pitchers have that confidence in it before they even think about using it in a game.

“The first step is to try to implement it in catch play, get guys to start playing catch with it in between. Then, once they start feeling comfortable, they feel like it’s consistently moving, then we take the step of putting it in the bullpen,” Hottovy said. “That timeline is different for every guy. Some guys it may take two days, other guys it may take three weeks. It just really depends on the comfort level, what they can do, and what else we’re working on with guys.”

Like Hottovy said, the process is different for every one.

Hendricks has taken opportunities to play around with it, for sure, but he’s also still trying to rediscover what’s worked best for him consistently. When Hendricks is struggling and there’s a list of things he and his coaches want to work on, developing a slider gets put on the back burner.

It’s not like the Cubs are still in spring training. At this point, if Hendricks is focused on other things in between starts, there’s not a whole lot of time to build enough confidence to use a slider against opposing hitters.

But that’s where seeing someone like Thompson incorporate the pitch into his game can help. It might be weird to say that Hendricks “looks up to” Thompson, but Thompson is certainly someone whom Hendricks has consulted for information on his process.

“He was the first guy I went and talked to about how he’s throwing his, what he thinks about, what he tries to do,” Hendricks said. “… Those are the guys you want to talk to. Those are the guys you look up to. It’s similar to somebody asking me about a changeup. I want to go find these guys who do it the best and really pick their brains, so I can really know what I’m trying to look for, I guess, when I do start using it.”

Now that he’s had a couple of solid consecutive starts, perhaps there will be more opportunities to play around with the slider — and if he wants to, he can look at Thompson as an example of how quickly it can be implemented.

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Hendricks hasn’t often looked like “The Professor” over the last two seasons, but that’s not necessarily why he could be trying to learn a new pitch at 32 years old.

It’s something Hendricks has had in the back of his mind even before his struggles started. Have his issues sped up that process? Possibly, but the idea of evolving as a pitcher also comes into play. Unless he makes some changes — like, of course, adding a slider — there’s no telling how long the issues that have plagued him might persist.

In Moskos’ mind, these conversations were being had not solely because he’d been struggling, but also because the Cubs see implementing a slider as another way to keep Hendricks pitching at a higher level for a longer period of time.

“I think it’s more about just, ‘Hey, you’re getting older. The game knows who you are. You’re very regimented in what you do, how you attack guys,'” Moskos said. “‘Could adding a weapon give them a different wrinkle that guys haven’t seen that buys you a couple more years, a few more years?'”

Moskos referenced future NFL Hall of Fame quarterback Tom Brady’s conscious decision later in his career to dedicate different things to his offseason program that have allowed him to play longer. That’s a line of thinking Moskos believes could benefit Hendricks as he nears the eight-year anniversary of his major league debut on July 10.

“I think that now,” he said, “we can kind of take that approach (to Hendricks): ‘OK, you’ve done this for a very long time. How do we buy you more time? How do we get you more years? Do you need to continue doing what you’re doing? Do you need to add a pitch? Do we need to change the locations that you throw a particular pitch to?’

“It’s all about, ‘What can we do to make you the best version of yourself?'”

The best version of Hendricks has always been someone who is going to beat you with pinpoint command, not by blowing fastballs by you. He’s certainly shown flashes of that since the start of 2021, but that version hasn’t been around as often as the Cubs would’ve liked.

Is it possible, then, that moving forward, the best version of Hendricks is the one who has mastered the slider?

“I’ve had the thought in my mind for a while,” Hendricks said. “It’s just, when is this going to have to come and be a part of my game?”

Well, Kyle, that’s the question everyone looks forward to being answered.