Every MLB Playoff Team's October X-Factor

October baseball is when X-Factors become the deciding factors.

Will key players who have been slumping rise to the occasion?

Can guys who caught fire in September keep that flame burning through October?

Which middle-of-the-rotation starting pitchers have a gem or two in their back pocket, ready to be unleashed for a career-defining moment?

Each of the eight remaining teams has potential X-factors throughout its roster, but we've identified the biggest one liable to seal their fate in the postseason.

ATL | CLE | CWS | LAD | MIL | NYY | SD | TB

Atlanta's X-factor could just be its right-handed bats in general. Ronald Acuña Jr. has been very streaky this season. At this point, it's a pleasant surprise any time the Braves get anything positive out of Ha-Seong Kim or Sean Murphy.

But it was Austin Riley who delivered the game-winning three-run haymaker off Jhoan Duran in Game 1 of the wild card round. It's Austin Riley who has started almost every game at third base this season, regardless of whether he has been hitting worth a darn as of late.

For the most part, though, he hasn't been hitting well.

Riley finished the regular season with a mediocre .662 OPS against left-handed pitchers, while having a nearly identical .651 mark against right-handers. After batting either fourth or fifth in each of his first 26 games, his average spot in the batting order went from 4.5 at the end of April to 5.5 in May, 6.3 in June/July and 7.5 in August/September.

He entered the NLDS at 4-for-32 with 17 strikeouts in his career against the Dodgers' big four of Yoshinobu Yamamoto, Tarik Skubal, Blake Snell and Tyler Glasnow.

Can he rewrite that narrative and become Atlanta's hero again?

Or is he going to be a black hole in the bottom third of a lineup that struggles to create traffic on the bases?

For most of the regular season, Colson Montgomery was batting in the heart of Chicago's lineup. We're talking 78 games started in the cleanup spot and 58 more in either the 3-hole, 5-hole or 6-hole.

Aside from one appearance as a pinch hitter in early April, it wasn't until mid-September that he batted seventh or eighth in the lineup for the first time.

When he landed in the 9-hole in Game 1 of the wild card series against Houston, it was his first time filling that spot this season.

Well, what's a bigger X-factor than a guy with 31 home runs—32, if you include his 432-foot tank job off Miguel Ullola in Game 1—batting last in the lineup ?

Granted, there's a reason he's down there.

Over his final 68 regular season games, Montgomery had a .539 OPS, striking out in 115 of his 282 trips to the plate. Shrink that data set to just his final 23 regular season games and he went 6-for-77 (.078) with two home runs and 40 strikeouts.

Montgomery finished the season with 227 Ks, breaking MLB's all-time single-season record. Although he did hit a solo home run on Tuesday, he proceeded to whiff in three of his six subsequent plate appearances against Houston.

By the way, his 35.6 percent strikeout rate for the year was only ever so slightly worse than Munetaka Murakami's 35.4 percent mark. They likely would have been No. 1 and No. 2 on that dubious single-season leaderboard if Murakami hadn't missed a month of action.

The White Sox basically have not one but two Joey Gallos in their lineup, liable to combine for three home runs and 16 strikeouts in a five-game series.

Tanner Bibee was Cleveland's Opening Day starter.

In his 33 turns through the rotation, though, he went 7-15. The Guardians went 12-21 in total.

Poor run support played a major role in that. In five of the 16 times Cleveland was shut out this season, Bibee started. The Guardians also scored four or fewer runs in 17 other games when he started.

That's how you suffer 15 losses while tossing 19 quality starts.

This wasn't a "Jacob deGrom winning the Cy Young with a 10-9 record" sort of situation, though. Bibee also had some real duds en route to his 4.36 ERA and 4.52 FIP. Whether he'll shine or splinter in his first start of this postseason is anyone's guess.

Six times—three in September alone—Bibee allowed at least five earned runs while failing to complete five innings.

One of those six duds came against the White Sox, who shelled him for home runs in each of the first three innings of a July 5 loss. However, that misstep came just 11 days after he held the White Sox scoreless for six innings in what ended up being a key extra-innings victory.

Can he deliver the goods in a pivotal Game 3?

Can this offense help him out in a big way, as it did down the stretch? Four of the five times this season that Bibee received at least seven runs of support were in his final four starts. It would be massive if that trend continues.

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Shohei Ohtani led the Dodgers with 30 home runs during the regular season. At .889, he also had the highest OPS among Dodgers who made at least 50 plate appearances. He narrowly missed leading the team in runs scored (89), runs batted in (81) and stolen bases (11).

Meanwhile, Freddie Freeman led the Dodgers in hits (167), doubles (32) and batting average (.288).

Over the past couple of months, though, they simply have not been the same leaders.

Freeman hit .237 with just six extra-base hits over his final 45 regular season games. After finishing each of the past 13 seasons with an OPS of at least .854, he ended that streak by putting up a .589 mark from August 2 onward.

Ohtani did not homer in his final 18 games, posting a .503 OPS of his own dating back to August 19. Prior to that, his longest homerless drought since switching LA-based teams was 11 games, so he is in uncharted waters in Dodger blue.

Now, the good news for the twice-reigning champs is that their other stars have been bringing the thunder as of late:

If that quartet stays hot, the Dodgers could be fine regardless of what Ohtani and Freeman do. But it sure would be easier to three-peat if those two key bats atop the lineup wake up in October.

X-Factor : Those OTHER Starting Pitchers

Over the course of the regular season, it gradually became impossible to start talking about the Milwaukee Brewers without mentioning Jacob Misiorowski within the first sentence or two.

What he accomplished was legendary, leading the majors in ERA, FIP, WHIP, strikeouts, K/9 and H/9. His 232 ERA+ was the highest mark by a qualified pitcher (excluding 2020) since Pedro Martínez's historic 2000 campaign (291).

But those Red Sox didn't even make the postseason because the rest of the starting rotation fell somewhere between "mediocre" and "terrible."

The Miz can't make every postseason start for the Brew Crew. Logan Henderson should be a strong second fiddle behind Misiorowski.

In 18 starts this season, he had a 2.47 ERA, a 0.84 WHIP and 10.1 K/9. Among pitchers who logged at least 90 innings, that WHIP was good for second-best in the majors , behind only his teammate at 0.80. Henderson has yet to allow more than three runs in an appearance this season, going at least five innings in all but the first one.

A Dustin May / Shane Drohan / Kyle Harrison conundrum—or Misiorowski on three days' rest—in Game 4?

We know better than to just assume that every Miz start is going to be a Milwaukee win, right? It worked out that way in 20 of his final 24 starts of the regular season, but note that the Tigers went just 3-3 in Tarik Skubal's postseason starts over the past two seasons—never once giving him more than three runs of support.

The soon-to-be-named NL Cy Young winner needs some support from both the bats and the starting pitchers around him.

Three Yankees appeared in at least 40 games at shortstop this season. Let's just say it wasn't because they had trouble choosing between superstars.

José Caballero was one of them, ending the year with a .655 OPS. Anthony Volpe was only slightly better at .658. George Lombard Jr. was the most productive of the bunch at a .699 OPS.

Not exactly "Peak Derek Jeter" batting figures from that key spot in the field.

Moreover, during one rough stretch in August, the rookie Lombard committed an error in six consecutive games. Overall, there were 20 "E6" rulings against the Yankees in 2026.

However, Lombard finished with a flourish at the plate and looks to be in great shape to lock down the gig for years to come. He hit four home runs and posted an .885 OPS over his final 11 regular season games before going 4-for-8 in the wild card round against Boston.

What if the sloppy defense rears its ugly head, though?

Most of them were confined to one brutal week, but nine errors in 42 games played is an alarming total. His .947 fielding percentage ranked dead last among the 44 shortstops who logged at least 350 innings played. With 49 bunt hits this season—the most of any team since the 2008 Minnesota Twins—the Rays sure can make you pay for less-than-stellar infield defense.

Also, prior to that strong 11-game run to finish the regular season, Lombard had been hitting .145/.206/.242 over his last 18 games.

New York could be in danger if that bat resurfaces.

Most of our X-factors are of the "It'd be huge if that player/position provides legitimate value for a change for the rest of October" variety.

With Ty France, however, having him become arguably the most valuable player on the Padres roster has been one of the biggest X-factors in all of Major League Baseball in 2026.

Over the previous two seasons, Seattle, Cincinnati, Minnesota and Toronto each either traded him away or let him walk in free agency after he gave them a sub-.700 OPS.

Between getting a minor league contract and starting in just two of the Padres' first 12 games, it's clear he was never expected to be a major contributor in San Diego, either.

He probably wouldn't have even made the roster out of spring training if Sung-Mun Song had been healthy.

Where would the Padres be right now without France's .865 OPS, though?

He was their spark early in the year when Fernando Tatis Jr. couldn't buy a home run and Jackson Merrill struggled to get going. He has remained their rock, batting .320 in July, .303 in August and .313 in September while starting at first base and batting cleanup on a near-daily basis.

France has already carried that momentum into the postseason, delivering four hits in the wild-card sweep of the Cubs.

Tatis, Merrill, Manny Machado and Xander Bogaerts are the Padres' well-paid stars most fans expect to be the biggest reasons this team either stuns the Brewers or departs in the NLDS. But it's France (and his Gold Glove at first base) that may be the biggest determining factor of all.

We'll tell you this much about this X-factor: Don't expect any home runs.

Chandler Simpson entered this postseason having made 2,248 plate appearances between the minors and the majors since the Rays drafted him in 2022. His lone four-bagger was of the inside-the-park variety at Double-A Montgomery in 2024.

What Simpson lacks in power, though, he more than makes up for with speed.

When he steps to the plate, you can almost take it to the bank that he's going to put the ball in play. Simpson has either walked or struck out in just 20 of his last 242 plate appearances.

With 153 singles this season, he had 14 more than his closest challenger. He hit .345 over his last 82 games.

And holy infield hits, Batman. Ichiro Suzuki was the patron saint of slap singles, averaging 44.0 infield hits per season from 2002-10. But with 42 of them this year, Simpson became the first player with at least 35 in a single season since Dee Strange-Gordon's 36 in 2015.

Simpson also led the American League with 46 stolen bases—while "leading" the majors with 14 times caught stealing.

In other words, the real fun begins once he gets on base.

He's a quality fielder, too, able to cover a ton of ground in left field with his speed.

Wouldn't surprise anyone if he flips a postseason game with his legs.