Is defense the World Series X-factor?

From the start, the 2022 Phillies built themselves to slug over everything. It's been true since they added Kyle Schwarber and Nick Castellanos and banked on their bats overwhelming the defensive holes they created. And it has Philadelphia on the doorstep of a World Series title.

The lineup the Phillies constructed has blown through the playoffs on big home run after big home run. But the Astros are the most complete opponent the Phillies will face -- an elite hitting, pitching and fielding team.

Can the Astros take advantage of their balanced skill set and make defense the X-factor of this World Series? Can Bryce Harper & Co. pull off one last defensive upset and bring a championship to Philadelphia?

Let's break it down.

On paper, this looks like as big of a defensive mismatch as it gets. Here are the best and worst fielding teams in 2022, according to Statcast's Outs Above Average.

Best/worst team defenses by OAA, 2022
1. D-backs: +44
2-T. Astros: +30
2-T. Padres: +30
…
28. Giants: -32
29. Phillies: -35
30. Nationals: -51

The Astros are second-best. The Phillies are second-worst. The difference between them is 65 OAA, translating to a difference of 54 runs prevented. That's huge.

The gap between the Astros and Phillies is by far the largest between team defenses in a World Series matchup in the Statcast era.

Will that be the deciding factor, since both teams feature deep offenses led by MVP-caliber hitters and strong pitching staffs led by ace-caliber starters?

The answer isn't so simple, for three key reasons.

1. The Phillies already beat the NL's best defensive playoff teams.

Take another look at the team OAA leaderboard. Notice the teams right next to the Astros at the top?

It's the Padres, who were tied for the second-best defense at +30 OAA, and the Cardinals, who ranked fourth at +24 OAA. What do they have in common? The Phillies just beat both of them in the playoffs on their way to the World Series.

Philadelphia going bat-first across its position-player group has paid off in the team's run through the National League playoff field. In the Wild Card Series, it was the Cardinals' defense that failed them, with missed ground balls by Tommy Edman and Nolan Arenado opening the door for Philadelphia's ninth-inning rally in Game 1. And in the NLCS, even the Padres' slick double plays between Ha-Seong Kim and Jake Cronenworth, smooth catches from Trent Grisham in center field and a defensive clinic from Manny Machado at third base couldn't save them.

The Phillies have already knocked off two top-five fielding teams in MLB this postseason. There's one left to go.

But the Astros have a relentless, hard-hitting lineup that can make a team pay for any defensive miscues -- just like they did in their ALCS sweep of the Yankees.

So it might not be enough for Philadelphia to just try to outmash the Astros, because the Astros, with their Altuve-Pe?a-Alvarez-Bregman-Tucker-Gurriel battering ram at the top of the lineup, can hit with anyone.

But there's more to this postseason Phillies team. And the 2021 Braves, who acquired bat-first, defense-last Jorge Soler and Eddie Rosario and played them both in the outfield during last year's playoffs, have already offered a blueprint on how to beat a superior defensive Astros team in the World Series.

2. The Phillies have gotten better on defense … especially in the infield.

When the Phillies were at their worst early this season -- going 10-18 in May to fall eight games under .500 -- their defense was at its worst. The Phillies were sitting at -26 Outs Above Average after a horrendous month of May where they posted an MLB-worst -21 OAA.

But they got better. In June, they were right around average, and by July, their team defense jumped to +5 OAA, tied for seventh-best among all teams that month.

The big improvement is in the infield -- and that's showing up in the playoffs. Philadelphia's outfield defense is still bad, with Bryce Harper forced to fill up the DH because of his elbow injury, putting Schwarber (-13 OAA) and Castellanos (-10 OAA) in the corner outfield.

The infield is another story. From April through June, the Phillies' infield defense sat at -17 OAA, a problem exemplified by Alec Bohm's early-season defensive struggles at third base.

But from July through the end of the regular season? That infield turned things around to a +5 OAA, including two top-10 months in July and September.

Phillies' infield OAA by month
April: -3
May: -13
June: -1
July: +4
August: -2
September: +3

Opening Day through June: -17 OAA
July through end of season: +5 OAA

Philadelphia's infielders are also helped out by the team's pitching staff, which induces some of the weakest contact on the ground of any team. The average exit velocity of ground balls allowed by Phillies pitchers in 2022 was just 84.8 mph, tied for third-lowest in MLB. Only 30.4% of those grounders were hard-hit (95-plus mph), the third-lowest rate in the Majors.

The Phillies even won over 11-time Gold Glove-winning Mets broadcaster Keith Hernandez with their improved fundies.

3. The teams on the field in the World Series are closer than you think.

With the World Series about to begin, the gap between the Phillies and Astros' defense isn't as wide as it looks on the OAA leaderboard.

The teams are different. The defensive looks they are rolling out in the playoffs aren't the same as the ones they had over the course of the regular season. Here are some key factors on both sides:

• The Phillies have Bryson Stott at shortstop now, Didi Gregorius and his -30 OAA in Philadelphia long since released. Stott's +2 Outs Above Average this postseason leads all fielders on the Phillies and Astros entering the Fall Classic.
• They have Jean Segura back at second base after he missed two months this summer with a fractured right index finger. Segura has +4 OAA at second base this season.
• They added Brandon Marsh at the Trade Deadline to take over center field. Marsh's +8 OAA this season made him a top-10 defensive outfielder.

• Philadelphia also acquired Edmundo Sosa (+9 OAA this season, +5 with the Phillies), who can play third base or shortstop and has been a valuable late-game defensive replacement during the postseason for Bohm (-8 OAA).
• Yordan Alvarez has been in left field for six of the Astros' seven playoff games. Though an elite slugger, Alvarez had -8 OAA this season and has -3 OAA in the postseason, worst among any fielder on the Astros or Phillies.
• Houston traded away Jose Siri to the Rays, whose +15 OAA ranked third among all outfielders in 2022, although Chas McCormick is still a very good center fielder (+7 OAA).

Now what you have are two teams who are both playing solid defense in the postseason. The Phillies are at +2 OAA in the playoffs, the Astros are at +1 OAA.

The Astros are still the better fielding team -- that season-long gap isn't meaningless. But the Phillies have a chance to prove they can make the plays to stop Houston from turning its defensive edge into a World Series-winning advantage.