Let's take a look behind the numbers for Houston's DH and Atlanta's left fielder as their teams prepare to go head to head.
Yordan Alvarez, Astros
ALCS stats: .522 AVG, .870 SLG, 1.408 OPS, 1 HR, 5 XBH
Why he's so hot
• He's jumping on the first pitch
Alvarez isn't giving pitchers the chance to put him away deep in an at-bat. In the American League Championship Series, he got five hits on the first pitch of an at-bat, the most of any player in either LCS. Those included his home run and two-run double off Chris Sale in the pivotal Game 5. He also had two more hits on the second pitch of an at-bat, including his RBI double to open the scoring in the clinching Game 6. Alvarez's aggressive approach is paying off big for the Astros.
And if he doesn't get his pitch early, he can still outlast a pitcher -- Alvarez had three hits against the Red Sox in full counts.
• He's going the other way
Here's the spray chart of Alvarez's hits in the ALCS. Seven of his 12 hits went to the opposite field, easily the most opposite-field hits of any player in either LCS (Ozzie Albies was next with four for Atlanta).
That was no accident either. The Red Sox were trying to pitch Alvarez away -- look at the heatmap of where he was pitched in the series. And then look at some of the swings he took against those pitches. He was looking to drive the ball the other way. That strategy makes a lot of sense, too, considering Alvarez's power and the short left fields at both Fenway Park and Minute Maid Park.
• He's ruining the platoon advantage
Alvarez hurt the Red Sox badly in lefty-lefty matchups, when you would think the pitcher would have the advantage. Eight of his 12 hits were against left-handed pitchers, and he batted .615 and slugged 1.077 against Boston's lefties.
• He's killing velocity
Alvarez thrived against the Red Sox's hard throwers. He went 5-for-8 with two doubles against 95+ mph fastballs in the ALCS. His expected wOBA against those pitches -- that's Statcast's overall offensive metric based on a hitter's quality of contact -- was .562, compared to the .338 xwOBA posted by all hitters against 95+ mph velocity this postseason.
In the regular season, by contrast, Alvarez batted only .156 with a .285 xwOBA against 95+ mph fastballs.
How the Braves could get him out
• Try pitching him backwards
Of Alvarez's five first-pitch hits in the ALCS, four came against fastballs, including the homer and the double off Sale. The one that came against a secondary pitch was a soft ground-ball hit against Sale's slider that beat the shift through an empty left side.
The Red Sox threw Alvarez a first-pitch fastball in two-thirds of his plate appearances in the ALCS. The Braves could try starting him off with breaking or offspeed stuff in the World Series.
They have the pitching staff to do it. Alvarez hasn't seen a whole lot of curveballs lately -- the Red Sox threw him only 5% curves -- and the Braves' rotation features two pitchers with great ones in Charlie Morton and Max Fried. In the Atlanta bullpen, closer Will Smith throws tons of sliders and will likely see Alvarez in at least one big spot.
• Bust him in
The Red Sox went after Alvarez on the outside part of the plate, and he killed them. Maybe the Braves will want to shake up the approach with their fastballs. Morton's front-door two-seamers and relief ace Tyler Matzek's explosive four-seamers seem like they could be weapons for attacking Alvarez inside.
Alvarez has a few hits against inside fastballs during the playoffs, but none for extra bases. And when he got out in the ALCS, most of those outs came against fastballs in.
• Go offspeed when they can
Alvarez did some damage against breaking balls in the ALCS, with a triple, double and two singles against sliders and curves. But he didn't have any hits against offspeed pitches (changeups or splitters) and those pitches got him out a few times. A Braves pitcher like Ian Anderson, who showcases an excellent changeup, could find success against Alvarez there.
If you want Alvarez to swing and miss, your best bet is to go offspeed -- he whiffed on half his swings against offspeed pitches in the ALCS, and his 29% whiff rate against offspeed pitches in the regular season was his highest against any pitch group (fastball, breaking or offspeed). Offspeed was the only kind of pitch he posted a negative run value against (-2 runs, vs. offspeed, compared to +14 runs vs. fastballs and +9 runs vs. breaking balls).
Eddie Rosario, Braves
NLCS stats: .560 AVG, 1.040 SLG, 1.647 OPS, 3 HR, 5 XBH
Why he's so hot
• He's turning on the down-and-in pitch
In the National League Championship Series, the majority of Rosario's hits came against pitches in the down-and-in regions of the strike zone, which you can see by the pitch chart of his base hits against Los Angeles.
He took advantage of the Dodgers' secondary pitches in that area especially, notching multiple hits off Walker Buehler's cutter and Julio Urías' curveball, plus others off Tony Gonsolin's splitter and Corey Knebel's knuckle-curve and a couple of Buehler changeups that stayed down but leaked more over the middle of the plate.
• He's been great with two strikes
Going down in the count hasn't bothered Rosario, whose two-strike hitting was exceptional in the NLCS. He had six hits with two strikes in the series, tied with the Dodgers' Trea Turner for the most in either LCS, and he belted a pair of two-strike home runs.
That gave Rosario a .462 batting average and 1.154 slugging percentage with two strikes in the NLCS. Overall this postseason, hitters are batting .164 and slugging .262 with two strikes.
• He's hitting lefties, too
Like Alvarez's, Rosario's lefty-lefty platoon splits in the NLCS were great. He went 6-for-10 with a homer, a triple, a walk and only two strikeouts against L.A. left-handers. Both those extra-base hits came against Urías, and Rosario also had two hits and a walk against lefty specialist Alex Vesia.
That's a big difference from the regular season, when Rosario had an OPS of just .651 vs. lefties.
• He's killing spin
Where Alvarez crushed velocity in the ALCS, Rosario crushed spin in the NLCS.
Against breaking balls with a spin rate of 2,700 rpm or higher, Rosario went a perfect 4-for-4. Three of those hits came off Urías' curve, and the other against Knebel's knuckle-curve. Rosario has handled high spin well all year, actually, with a .353 batting average and .647 slugging percentage against 2,700+ rpm pitches in the regular season.
How the Astros could get him out
• Get the fastballs down and away
Rosario did a good job keeping his swing level and handling fastballs in the upper part of the strike zone against the Dodgers. Unlike many hitters who are vulnerable against high heat, and lefties who are vulnerable up and in, the best place to attack Rosario might actually be down and away.
Rosario doesn't have a hit against a fastball in the low-away regions of the zone this postseason, and those have been his cold zones against fastballs all year. He doesn't hit those fastballs as hard, and his results are much worse against them.
• Get the soft stuff away, too
With all the hits Rosario got against the Dodgers on secondary stuff down and in, Los Angeles was able to get him out when they got those pitches away, on the outside part of the plate or out of the strike zone. Here are the outs he made in the NLCS.
• Use their sliders
Rosario swung and missed on 56% of the hacks he took against sliders in the NLCS, and his whiff rate vs. sliders is at 50% for the postseason. He's not swinging and missing at much of anything else, so the Astros pitchers who have good sliders -- especially their slider-heavy bullpen chain that includes Phil Maton, Ryne Stanek, Kendall Graveman and closer Ryan Pressly -- might want to use them.