Someday soon there will be a new generation of Justin Verlanders and Max Scherzers and Clayton Kershaws. Who will be those aces of the years to come?

You might think of Walker Buehler, or Jack Flaherty. But here's a surprise name. Somebody a fan might forget, but the Major League hitters who face him sure don't.

It's Shane Bieber.

Even with his All-Star Game MVP Award and his 3.28 ERA and 259 strikeouts in 214 1/3 innings last year, Bieber can get lost in the crowd behind the dominant big-name aces of the AL like Verlander and Gerrit Cole, and the other arms to come out of his own Indians rotation, like the since-traded Corey Kluber and Trevor Bauer. But when MLB.com polled players for their Vault predictions, guess who kept coming up for most wins, strikeouts and Cy Young Awards of the 2020s? Bieber.

Here's why the players -- including elite sluggers like Nelson Cruz, who's seen tons of aces in his day -- think the Indians' breakout 24-year-old right-hander is so nasty.

YOU HAVE TO TRY TO HIT HIM ...

Bieber is not going to walk you. He was never going to walk you. His walk rate as a rookie in 2018: 4.7%. His walk rate as a sophomore in 2019: 4.7%.

That's not just eerie symmetry, it's really low -- fewer than one walk in every 20 batters faced. Last year Bieber ranked sixth among qualified starters, in a "5% or lower" group with pitchers like Hyun-Jin Ryu, Zack Greinke, Kyle Hendricks, Scherzer, Verlander and Buehler.

Bieber's not going to beat himself by issuing free passes. The problem was, his rookie season, the hitters beat him; he had a 4.55 ERA to show for it. They're not beating him anymore.

BUT YOU CAN'T ...

It's good to not walk people. It's better to not walk people and strike people out. That's the hallmark of mastery of command. Otherwise you're just Mike Leake. And that's the difference between 2018 Bieber and 2019 Bieber.

While Bieber's walk rate stayed identical, his strikeout rate shot up from 24.3% to 30.2%. That gave Bieber a strikeout rate 25.5 percentage points higher than his walk rate, the fifth-best K-BB% among starters. The only pitchers better were Gerrit Cole, Verlander, Scherzer and Jacob deGrom. So what happened? Bieber's arsenal improved across the board.

First, he turned his fastball into a rising fastball. In 2018, his four-seamer had exactly average rise. In 2019, with the same 93-ish mph velocity, he got +2.4 inches of rise above average. A rising fastball is a lot tougher to hit, especially when you pair it with the new-and-improved breaking balls Bieber was throwing -- a slider-curveball combo paralleling fellow Cleveland-grown strikeout artists Mike Clevinger and Bauer.

Bieber's slider and curveball were a lot different in 2019. He threw both pitches significantly harder -- his slider velo went from 83.7 mph to 85.0 mph, and his curve went from 80.0 mph to 82.7 mph -- and transformed their action into more strictly vertical movement. Harder and straight drop instead of sweeping break? That tunnels a lot better with a true-spin, rising fastball.

The swing-and-miss numbers tell the story. Hitters whiffed on nearly half the swings they took at Bieber's two breakers, and in total? Bieber got 364 swinging strikes on his breaking balls (200 on the slider, 164 on the curve), more than any pitcher in baseball.

Most swinging strikes on breaking pitches in 2019
1) Shane Bieber (CLE): 364
2) Patrick Corbin (WSH): 355
3) Robbie Ray (ARI): 302
4) Justin Verlander (HOU): 284
5) Clayton Kershaw (LAD): 277

Bieber got 145 strikeouts on his breaking pitchers -- fourth behind Verlander, Corbin and Kershaw -- to go along with the 100 he got with his rising four-seamer. (He only sprinkles in his changeup, with a purpose … you'll see why later.) But there's another reason for Bieber's success beyond better stuff. He was a wiser pitcher.

BECAUSE BIEBER LEARNED HOW TO ATTACK ...

There is such a thing as throwing too many strikes. Bieber was. But he evolved.

Bieber's in-zone %
2018: 53.6% -- 10th-highest of 147 pitchers, min. 1,500 pitches
2019: 46.4% -- 104th of 143 pitchers, min. 1,500 pitches

Bieber's "meatball" % (middle-middle pitches)
2018: 9.0% -- 4th-highest of 147
2019: 6.4% -- 98th of 143

The key is that Bieber learned to go out of the zone without increasing his walks. (He got hitters to chase nearly a third of the time.) And all those fewer pitches thrown right down the middle meant a lot fewer opportunities for hitters to do big damage against him.

The big step Bieber took to keep hitters swinging and chasing was ... he stopped throwing so many fastballs.

Bieber cut his four-seam usage from 57.4% in 2018 down to 45.7% in '19. And that shift went toward distributing his pitch mix more evenly -- Bieber's slider, curveball and changeup usage all increased by about four percentage points.

Bieber used to throw a lot of fastballs in two situations in particular: to try to put away hitters in two-strike counts, and to get back into the count when behind. Now he throws more of both breaking balls to get Strike 3, and he uses his slider in hitter's counts where he used to throw only fastballs.

How appropriate for an Ace of Tomorrow. Who throws fastballs anymore? And the fastball count is dying. Bieber is taking his repertoire and approach into the future.

NO MATTER WHAT KIND OF HITTER YOU ARE.

There is one last piece to Bieber solving the puzzle. Everything up to this point -- the straight rising four-seamers, the dual breaking balls, the pitch mix strategy -- isn't just blanketed onto every batter he faces. Bieber takes a targeted approach to attacking right-handed and left-handed hitters.

He's not unique in doing this, of course. Every ace worth his salt approaches righties and lefties distinctly, whether by emphasizing certain pitch types to each or whatever. But to understand Bieber's success you need to look at his style of attacking the two halves of the platoon.

Against righties: He overwhelms them with a four-seam/slider one-two punch.
Against lefties: He eats them up with knuckle-curves, and flashes the changeup.

Bieber loves to take advantage of two traditional righty/lefty dead zone pitches -- the low-and-away slider to righties, and the down-and-in curveball to lefties.

Facing a right-handed hitter, Bieber wears out the outside edge of the plate. His backspun fastball sets up his vertical slider perfectly, and the tunneling is beautiful when the pitches come in along the same vector. Nearly 90% of his pitches to righties are fastballs and sliders.

The four-seam/slider combo is why Cruz can't hit Bieber. Bieber threw Cruz 33 pitches last season; 31 of them were either four-seamers (13) or sliders (18). Cruz whiffed on three fourths of his swings, nearly all of those on down-and-away sliders. In seven at-bats, he got one hit and struck out five times.

Facing a lefty, Bieber's fastball usage stays constant, but his sliders become curveballs and changeups. That's why it's so important for him to have two breaking balls and an offspeed pitch in his arsenal. It's similar to what Blake Snell does, for example. The Rays ace also throws his curve and changeup nearly exclusively to opposite-handed hitters (i.e. for him, righties) and his slider mainly to same-sided hitters (lefties).

For Bieber, the slider's replacement against left-handed hitters manifests in two ways. The first is to bury curveball after curveball underneath a lefty's swing -- hitters like Bryce Harper and Yoan Moncada have fallen to Bieber with that approach. Bieber's curveball is basically his slider but with more drop.

The second is to use his changeup as a show-me pitch to set up his fastball along the same trajectory -- Shohei Ohtani struck out more than once against Bieber in just that way. The fastball is actually the out pitch, not the changeup, a "pitching backwards" type of approach.

It all works. It works to the tune of 259 K's. It's no wonder hitters hate to face Bieber, and think they're going to hate facing him for the next decade.