Think about the most memorable pitching duels from your lifetime of watching baseball. Conjure your favorite. What was it about that game that made it so indelible?

Chances are, that special memory did not involve a manager walking to the mound in the middle of the sixth inning and taking the ball from his starter. Or the seventh, or probably even the eighth. The ninth? Maybe. It's the best we can hope for at this point in baseball history.

Last season, there were just 15 pitchers to reach the 200-inning threshold that so many starters still point to as one of their primary objectives in a given season. That matched the season before for the fewest to reach that threshold in a non-strike season. In 2015, there were 28 pitchers to reach 200 innings. Ten years before that, there were 50. Thirty years before, there were 57. You can see where this is headed.

Grit, it seems, is on the wane.

"I love being a pitcher," future Hall of Famer Justin Verlander told ESPN.com during spring training. "When I first started playing baseball, I always envisioned myself as a pitcher. I idolized Nolan Ryan, that old-school grit. Being a fan of pitchers, I did appreciate [a great duel]."

Verlander has reached the 200-inning threshold ten times, one more than James Shields of the White Sox for the most among active pitchers. The all-time leader in that category is Don Sutton, still working in baseball as an announcer for the Braves. He had 20 200-inning seasons.

Shields has struggled in recent seasons, so it's easy to forget that for a while, when he was playing under current Cubs manager Joe Maddon in Tampa Bay, Shields became something like a 21st-century version of Old Hoss Radbourn. His 11 complete games in 2011 are the most any pitcher has had this century. To label Maddon as old-school or new-school would be inaccurate. It's more like he's Maddon-school. But, still, how did Shields convince Maddon to allow him to finish so many games?

"I remember in 2010, I hadn't had a complete game since 2008," Shields said. "I told him in spring training that I wanted to finish games off. He believed in me. He believed in the process and allowed me to go out there. At the end of the day, you've got to have the trust of your manager and you've got to have that mentality and work ethic."

As for Verlander, his potential was always clear. He was the second pick of the 2004 draft, and the team that didn't draft him -- San Diego -- would surely like a do-over. It didn't even take him a full minor league season for him to reach Detroit. His career numbers in the minors: 11-2 in 22 starts, a 1.42 ERA and 10.5 strikeouts per nine innings.

Nevertheless, there had to be a proving period once he joined the Tigers. There had to be a time when his manager, Jim Leyland, would realize that Verlander was a pitcher who deserved a long leash.

"I think I was fortunate," Verlander said. "With a manager who had some old-school tendencies. To be the manager he was, he blended them with new-school techniques, but still, down in the gut, he went with his instincts."

Stick a pin in that comment, because there's an emerging theme.

During the postseason last year, Verlander was a marvel while becoming the new prototype of a "finishing piece" -- the final ingredient to the Astros' championship recipe. He led all pitchers in the postseason with 36⅔ innings, including a crucial 2⅔-inning outing in relief. He had a complete game, beating the Yankees in Game 2 of the American League Championship Series with 13 strikeouts.

This was hardly surprising. Verlander long ago forged a reputation for his ability to work deep into games by managing his workloads early in contests. This ability allowed him to gather steam as games progressed, and often, his top velocity readings would surface during the latter portion of his starts.

"[Leyland] always told me, especially early on," Verlander said. "When I was younger and throwing 100, who am I going to bring in behind you that I think is better than that? Who am I going to bring in that has better stuff? That's what his process was. If we needed a big out late in a game, he would let me go get that out. That's also when I had my best stuff, typically."

There's a lesson: If you want to pitch deep into games, be better than the relievers behind you. In other words, be Justin Verlander.

Yet consider this: Verlander threw 124 pitches in that postseason complete game. He didn't reach 100 pitches in any of his five other playoff outings. He got to seven innings just one other time. And he still threw three more innings than any other postseason pitcher, with the Dodgers' Clayton Kershaw coming in second.

So it wasn't a Deacon Phillippe-type postseason for Verlander, but it was impressive nonetheless. Phillippe pitched during the first decade of the 20th century. It affirmed that even in 2017, there is a place for a pitcher who can shoulder a heavy load. Houston manager A.J. Hinch was able to leverage that trait in Verlander because it was well-established. Verlander's performance was crucial for the Astros -- they likely would not have reached the World Series, much less won, if not for him.

"I established myself as a guy who gets stronger as the game goes along," Verlander said. "The rest is history. I had the physical ability to do it, but also the right timing and the right manager and the right organization."

Given that combination of factors, it makes you wonder. How many of these vintage pitching performances will we see in the future? Will the playoffs of the next decade be more marked by the Andrew Millers of the world, or the Verlanders?

Everything is working against the Verlander model. With each season, more and more innings are shifted from the rotation to the bullpen. Increasingly, teams are adhering to analytical precepts that tell them it's not a good idea to let a starter face a lineup more than two times through the order. At the same time, teams are ever more cautious with the workloads of young pitchers as they wind their way to the big leagues.

These are trends that have been in place for decades and have accelerated in recent seasons. They show no sign of abating.

"To have a guy be able to prove that now?" Verlander said. "I don't know. I think it's going be tough. That's why it's kind of a dying breed."

Verlander led all pitchers in the 2017 postseason with 36 2/3 innings. Bob Levey/Getty Images

The postseason innings leaderboard is mostly dominated by wild-card-era hurlers, as you would expect. Verlander's total is tied for a modest 15th place. In 2014, the Giants' Madison Bumgarner set the single-season record with 52⅔ postseason innings thrown while leading San Francisco to a title.

If you need an indicator of just how much the role of the starting pitcher has evolved, consider this: No. 3 on that postseason innings list is Pittsburgh's Phillipe with 44. He set that mark in the very first World Series in 1903. There were no preliminary rounds -- he threw five complete games in that series.

Nowadays, feats of innings-related marvel tend to come in the form of long relief outings. If a pitcher goes nine innings now, it's not a product of stamina. It's one of pitch efficiency.

During the 1920s, 1 in 10 complete games were shutouts. By the 1960s, that had risen to 1 in 4. During the current decade, nearly half -- 48 percent -- of all complete games have been shutouts. Early in the 2018 season, one in which the weather has Major League Baseball on a record pace for team shutouts, three of the five complete games have been one-pitcher shutouts.

For a starter to convince his manager to finish a game, he basically can't give up anything. And even then, chances are he won't be allowed to finish. How are we going to find another Verlander like that? The Shohei Ohtani experience Keep track of the Japanese phenom's bid for greatness on both sides of the ball. Story »

"I think it's going to have to take the right player," Verlander said. "Somebody pretty similar to what I used to be able to do, that gets stronger as it goes on. Going to have to have tremendous stuff, because that's what you get coming out of the bullpen right now."

Meanwhile, the frequency of long relief outings is growing and growing. The number of relief outings of more than two innings grew to 628 last season, the most since 2006. This season, there have already been nine relief appearances of at least four innings. That includes the Cubs' Eddie Butler and Miami's Jarlin Garcia, who threw seven and six innings, respectively, in a 17-inning contest between the teams on March 30. If those outings had not come in relief, they would have counted as quality starts.

One way to read this is that the pitching-staff model that dominated from the late 1980s into this decade was found to be wanting. Many of us suspected this all along. Sure, it was fine and dandy to create all of these hyperspecialized relief roles. You could tell each pitcher what his job was and the player holding a particular job quickly latched on to it. Not everything changed, though.

"For me, and I don't know all the numbers, if you look at the past six to eight years, there aren't many teams that make the playoffs that don't have at least 900 innings from their starting staff," Shields said. "At the end of the day, it's a long season. You have to save your bullpen as much as you possibly can. It's our job as starters to save the bullpen. The starters that are coming up, they still have to have that mentality."

The problem a few years ago was that too many innings were being shifted from good pitchers to fringe pitchers. Top starters were getting plenty of work, but fringe starters were getting innings that now might go to a competent long reliever. As for leveraging relief innings -- forget about it. Teams have gotten much smarter on that front.

Great! The efficiency of pitcher usage is improving. We have more hard-throwing young relievers than ever. Often, they are a faceless, nameless lot, and because of their sheer quantity, they feel almost interchangeable. You might go to a game and see your team shut out the opponent on three hits with 15 strikeouts. It might take five pitchers to do it. A week later, you can't remember who pitched.

What we are losing in this process is clear. We're losing the man-to-man pitching matchups that used to so fixate us. We look at a table of pitching probables that might tell us that Jose Quintana is pitching against Alex Wood that day, but it's not completely true. The Cubs are playing against the Dodgers, and the pitchers are squaring off against their own pitch counts.

Nevertheless, that doesn't mean that we won't have Verlanders in the future. It just means that they will be that much more special.

"I think so," Astros general manager Jeff Luhnow said. "As pitchers stay in the game longer, the idea is that their quality declines because they are getting tired, or because batters are getting used to their stuff. The alternative is bullpen arms designed to get specific batters, or maximize their effort over three or four batters. They become the more attractive option for the manager deep in a game.

"Except when you have a Clayton Kershaw or a Justin Verlander or even a Dallas Keuchel, who the third time through the order they are still your best option relative to your bullpen. Except maybe for your closer. In the minor leagues, it's rare that pitchers get to go deep, but I do know that while we have limited our pitchers in the lower levels, once they get to Triple-A, we do want to make sure our starters have an opportunity to go deep into games."

From there, it'll be up to a pitcher-manager partnership at the big league level to push the envelope until eventually you find that you have a Verlander on your hands.

"It may be a smaller population of elite pitchers," Luhnow said. "But one of the hardest things a manager has to do is to take an ace out when he's not ready to come out. And they're never ready to come out. They always want to keep going. There are always going to be those guys."

Verlander seems to get better deeper into games and later in his career. His 140 ERA+ in 2016 and 132 last year were both well above his career average (124). Erik Williams/USA Today Sports

Managers just know. That's what you hear when the notion of the disappearing Verlander is broached. You'll know one when you see one.

"They'll always exist," Hinch said. "The elite pitchers in this league, guys who can get through a lineup the third time, they may become a little bit more unique. But, look, you want guys to go as long as they can. Any one particular game, any guy has a chance to go deep into a game.

"The guy who can do it over 30 starts in a season, or a 15-year career like Verlander has done, is a rare feat. For one, it takes health. The ability to go deep in a game will always exist in this game. The information will always tend to want you to get to your bullpen a little bit faster. But I can recite a lot of games during my short managerial career where I might have been foolish to take a guy out."

Remember your favorite pitching duel? Maybe it's on this list. That's a list of regular-season games since 1940 in which the starting pitcher for both teams posted a game score of at least 80. What does an 80 game score look like? Take this game from May 23 last season between the Cardinals and Dodgers. Lance Lynn held L.A. to one run over eight innings with 10 strikeouts. Kershaw went nine frames, and also allowed one run and struck out 10. That's a legit pitcher's duel, though the game went to extra innings and neither starter ended up with a decision.

There were four such games last season. There were none in 2016. There haven't been more than four in a season since 1990. During the 15-year period ending last season, there were zero or one pitching duels in seven different seasons. Sign up for free fantasy baseball Baseball is back, and so is fantasy! Get the gang back together, or start a new tradition.

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In other words, if you see at least one pitching duel this season of the type you're likely to always remember, there's about a fifty-fifty chance you've seen the only such game in that particular season.

This has all happened for a reason, of course. You can see it in league-level splits. For the average pitcher, here was last year's progression of OPS allowed per times facing a batter in a game: .738 the first time; 779 the second; .801 the third. The difference between the first and the third time seeing a hitter is roughly the difference between facing Jordy Mercer and Joe Mauer. Between individuals, there is plenty of variance. But you can see why the practice of limiting the exposure of starters is growing.

The benefit of all this to the health of starting pitchers is unclear. Last season, there were just seven pitchers aged 35 or older to throw at least 100 innings. That's the fewest since 1995, which was a truncated season. Raise the threshold to 150 and there were just two -- R.A. Dickey and John Lackey. Both are out of the league this year. So, if the trends of recent decades are paying off in terms of longer careers for starters, it's not immediately clear. In 2007, there were 14 starters aged 35 or older to log at least 150 innings.

Verlander is in his age-35 season and is better than ever. Literally. His ERA+ of 253 for his first three starts would by far be the best of his career if he maintained it for the full season. (Which he won't.) Still, his 140 ERA+ in 2016 and 132 last year were both well above his career average (124). Verlander is going strong, and is also a unicorn.

You can see the perceptions shift in the way day-to-day coverage of the game has evolved. Postgame questions about when a manager put the hook in a guy used to be standard fare. Now, they've slowed to a trickle, perhaps because even the media have come realize these decisions are now mandated more by organizational mantra than they are managerial preference.

The other night, after the Pirates beat the Cubs 6-1 and young starter Trevor Williams was allowed to face a portion of the Chicago order for a third time, that actually became line of inquiry afterward in Clint Hurdle's office.

"There are a lot of books out there right now that tell you that you can't do that," Hurdle said. "You're not supposed to do that. I tell our guys, 'OK, how are we going to figure out how to do that? The game is meant to be played at a certain level. If the guy has the stuff, go let him pitch and let him use his stuff."

But Hurdle is the same manager who pulled Williams after six hitless innings on April 1. Williams had walked five and thrown 85 pitches, but still, he hadn't allowed a hit or a run, and for most of baseball history, it would have been inconceivable to remove him between innings at that point of the contest.

Another counterpoint in the Hurdle universe: He allowed Jameson Taillon to complete a one-hit shutout against Cincinnati a week after Williams was pulled from his no-hit bid. Taillon needed only 110 pitches to finish that game, so it's not like Hurdle was abusing him.

Still, Pittsburgh held a five-run lead in the late innings and Hurdle could have replaced Taillon after eight to preserve his pitch count. But within the industry, things like complete games and shutouts still matter to those playing the game. It's just that now, they have to fall within a very specific set of usage parameters. Those parameters are managed by ... the manager.

Therein lies your answer when asking whether there will be Verlanders in the future. Such unicorns will spring to life because smart managers allow them to come into being. It'll be a gradual process for each emergent ace, but it will happen. And given how unusual these future workhorse aces will be, they will only be that much more valuable to their teams, not to mention the marketplace.

These things will continue to evolve. The prevalence of flamethrowers filling bullpens we see now could dry up. Ten years ago, that aforementioned problem of too many incompetent pitchers getting innings was certainly in part a problem of supply and demand. Now there are more capable relievers. This could change again.

We'll also see how things evolve in regard to the playoff structure. It used to be that teams would put all of their resources toward winning the pennant, because there was only one round to navigate after you'd won. Now, with ten teams getting in, often the top teams can project themselves into the October picture well in advance. Teams like the Dodgers and Cubs have taken this into account in recent years as they manage the workloads of their pitching staffs through the season.

The 2017 Astros are the prime example of that. From the middle of the season, there was little doubt that Houston would be in the playoffs. They had plenty of time to focus on the 18 postseason games it took to get the 11 wins they needed to clinch the franchise's first title.

Eighteen games -- each one an exhausting, self-contained adventure. Hinch had to keep his pitchers fresh for that run, even while positioning the Astros for the top seed. And when his bullpen faltered, almost en masse, he had to lean heavily on his starting pitchers. He was able to do that because of the work he did during the season to preserve those starters. And because of Verlander.

Maybe our best hope for future Verlanders lies in his bank account. Through the 2017 season, Verlander had earned $198.5 million dollars in big league salary. If the market for the middling starter is ebbing, as this winter suggested, the one for the elite, all-but-impossible-to-find starter like Verlander, Chris Sale, Max Scherzer and Kershaw seems to be just fine.

That means the incentive to push the envelope beyond being a two-times-through-the-order guy remains strong. And owners know all too well the unique effect a superstar starter can have at the turnstile. (It's Verlander day!)

The ace starter, the workhorse, the guy who can lift a team on his back and carry it across the finish line -- one-name guys like Gibson, Unit, Rocket, Koufax, Verlander -- these are the legends of the game. To have no more of them ... is an unpleasant thought.

If analytic trends were followed to their logical conclusion, another such legend might never again come into being. But while patterns of usage may be a more efficient way to win games over the course of a long season, or even multiple seasons, that doesn't mean magic will go out of the game. There are too many reasons for it not to.

Enjoy the aces. Relish those pitching duels, when they come. Thanks to generational talents and astute managers, they won't go away completely. Will they?

"That's a good question," Verlander said. "I don't know the answer to that."

Not exactly reassuring. As long as they don't go completely extinct, Justin Verlander, and his shrinking population of peers, will remain one of the wonders of big league baseball.

All it takes is one. Or two, if you want an old-fashioned pitching duel.