MLB playoffs X-factors in NLDS, ALDS: Mets, Phillies hit fastballs, Padres' flamethrowers have edge on Dodgers

The playoffs resume Saturday with four League Division Series openers

Major League Baseball's postseason will resume Saturday with the opening of the four League Division Series. Check out the complete 2024 MLB playoff schedule. These best-of-five matchups will represent the first time the top two seeds in each league have played this October. Additionally, they'll serve as the last stage of the postseason that features multiple series in each league. Whichever four teams win here will advance to the League Championship Series, where they'll compete for a spot in the World Series.

As is tradition, we here at CBS Sports like to provide an x-factor for each series ahead of the round. To explain exactly what we mean by "X-factor," here's what we wrote ahead of the Wild Card Series: "We tend to aim for under-the-radar or more granular components that tend to pit strength versus strength or strength versus weakness."

With that in mind, let's get to the point by highlighting one plausible X-factor for each divisional series.

1. Royals vs. Yankees

X-factor: Team speed

As we pointed out prior to the Royals' series against the Baltimore Orioles, they had three players record 30 or more stolen bases this season: star shortstop Bobby Witt Jr., third baseman Maikel Garcia, and outfielder Dairon Blanco. The Yankees, conversely, had no one top 30 stolen bases and had just three even get into double digits.

The disparity in team speed between the clubs goes beyond the stolen base. The Yankees ranked last in sprint speed and near last in advancement attempts during the run of play. The Royals ranked 12th in sprint speed and first in attempted advances. It's perfectly reasonable to suggest this is a battle of contrasts.

Of course, the Royals' more athletic style doesn't necessarily mean much. It doesn't matter how fast you can cross the plate so much as it matters how often you do it. The Yankees were the better team at that during the regular season, and that helps to explain why they won eight more games and have the home-field advantage.

Still, styles are said to make fights. We could see this one being fun on those grounds, even if we think other factors will actually determine the series outcome.

2. Padres vs. Dodgers

X-factor: Extreme velocity

Given Paul Skenes' existence, you probably could have guessed that the Pittsburgh Pirates threw the most pitches this season clocked at 97 mph or above. Did you know the Padres ranked second in that category and that those two teams were way, way ahead of everyone else? The Pirates threw nearly 3,000 pitches at that velocity while the Padres checked in just over 2,500; no other team threw even 1,900 pitches at 97 mph or above.

Five members of the Padres pitching staff chucked at least 150 pitches that hard: Robert Suarez, Dylan Cease, Adrian Morejon, Jeremiah Estrada, and Tanner Scott. That brigade of flamethrowers just might spot the Padres an advantage over the Dodgers. 

That's because the Dodgers ranked 15th in the majors in OPS against pitches thrown 97 mph or harder -- the Guardians and the Tigers were the only playoff teams with worse marks in this respect. (The Braves and Brewers were the best in this category, suggesting that perhaps it's not a particularly effective predictor.)

Teoscar Hernández, Mookie Betts, and Shohei Ohtani were the only Dodgers with an OPS above .800 against extreme heat. On the flip side, the Dodgers saw three likely starters (Freddie Freeman, Max Muncy, Miguel Rojas) finish with sub.-500 OPS against flamethrowers.

Will it matter? We'll find out. But if it does end up playing a role, expect it to manifest in the second half of games, when Suarez, Morejon, Estrada, and Scott are deployed out of the bullpen -- either to preserve a lead or a tie or to keep the deficit manageable. 

3. Mets vs. Phillies

X-factor: Fastballs

No team threw a higher percentage of fastballs (meaning four-seamers or sinkers) this season than the Mets. Heaters accounted for nearly 53% of their pitches. The Phillies weren't too far behind in that respect, chucking 51.5% fastballs (good for sixth in MLB).

Naturally, our area of concern here pertains to how these teams will hit those fastballs. The Phillies were a touch better at it during the regular season, out-OPSing the Mets on heaters by 22 points. Some of that gap can be explained away by park factors, however. This, then, looks like an instance of strength-on-strength without a clear edge.

For those wondering, the best fastball hitters on the Phillies were Kyle Schwarber and Bryce Harper, with each finishing north of a .900 OPS. Austin Hays, Nick Castellanos, J.T. Realmuto, and Trea Turner all had marks above .800. Only one Phillies batter with a chance to play in this series had a sub.-700 OPS against heaters: Johan Rojas.

On the other side, the Mets were led by Mark Vientos (he of the .988 OPS against fastballs) and Pete Alonso. Jose Iglesias, Francisco Lindor, Francisco Alvarez, J.D. Martinez, and Tyrone Taylor also finished above .800. As for the worst performers, the group of Harrison Bader, Jesse Winker, and Starling Marte all fell short of .700.

4. Tigers vs. Guardians

X-factor: Bullpens

If you enjoy watching parades of relievers or at least seeing the little stat box pop up whenever a new pitcher enters the game, then this series is most certainly for you.

The Tigers averaged the fewest innings per start during the regular season, at 4.6 frames a pop, and have already shown they're willing to employ a bullpen game in the playoffs. The Guardians, for their part, also ranked in the bottom 10 in innings per start -- that shouldn't come as a surprise since they recorded the fewest number of 100-plus-pitch starts this season, clearing the century mark five times in 162 tries.

On paper, the Guardians would seem to have an edge if this series goes full bullpen (fullpen, if you will): Cleveland ranked first in the majors in relief ERA during the regular season; the Tigers ranked fifth. Additionally, the Guardians led the league in shutdowns, averaging more than 2.82 of those per meltdown; the Tigers ranked ninth in shutdowns, posting 1.75 of those per meltdown. 

We write "on paper" because 1) who knows how the games play out; and 2) it's important to remember that these are liquid personnel situations. Cleveland is going to be using Erik Sabrowski, not Tyler Beede; Detroit is going to be calling upon Jackson Jobe, not Joey Wentz. You get the point: bullpens, more than any other unit, can look and perform like different beasts in October compared to April, June, or August.