2023 World Series: Rangers vs. Diamondbacks X-factors, including return of the stolen base

Game 1 kicks off Friday at Globe Life Field

The World Series will begin on Friday, with the Texas Rangers hosting the Arizona Diamondbacks in a matchup of unexpected pennant winners. The Rangers spent the summer proving they were legitimate en route to 90 wins. The Diamondbacks, conversely, snuck into the playoffs with 84 wins. They've since shown they can hang with the National League's most talented clubs.

As is the custom around here, we wanted to preview the series by breaking down a few potential "X-factors" that could determine the winner. If you suspect that "X-factor" is a vague term that enables the author to write about basically any aspect of either team they want -- well, yes, yes it is. That's the great power that comes with being on this side of the keyboard. So it goes.

With that fine print out of the way, let's get to it.

1. The four-seam fastball 

During the regular season, the Diamondbacks threw the fourth-highest percentage of four-seam fastballs in the majors. The Rangers, conversely, posted the third-best OPS against four-seam fastballs. This, then, is an instance where one team's strength will collide with the other team's strength.

The Diamondbacks pitchers most dependent on their four-seamer were -- no surprise -- mostly relievers. When it's time for Paul Sewald to pitch, the closer led the way with a 65% four-seamer usage rate. Two other relievers who figure to be on the roster (Slade Cecconi and Ryne Nelson) also cleared 50%. The fastball craze isn't isolated to Arizona's bullpen, however: starters Zac Gallen and Brandon Pfaadt were both above the 38% team average.

Mind you, this is a very surface-level analysis. We could get more granular here and pull out specific fastball traits that actually dictate what is a good or a bad matchup. We'll save that for the front offices in Arizona and Texas. Instead, we'll just note that the Rangers who, in theory, could present the biggest problems to those Diamondbacks pitchers are Mitch Garver, Corey Seager, Evan Carter, and Josh Jung. Each of the four had an OPS over .900 against four-seam fastballs during the regular season. 

2. The stolen base

If you've paid any attention to the Diamondbacks this year, you know that they like to steal bases. They finished second in the majors in that respect, behind only the Cincinnati Reds. Star rookie Corbin Carroll himself stole 54 bags, or just 25 fewer than the Rangers swiped as a team all season long.

The Diamondbacks stole two bases in two Wild Card Series games; five in three Division Series games; and nine in seven League Championship Series games. How many might they steal over four to seven World Series games? We'll have to find out, but just know that the Rangers are a tough team to run on.

Indeed, the Rangers allowed the fifth fewest stolen bases during the regular season. Catcher Jonah Heim doesn't necessarily rank highly in any of the quantifiable aspects of controlling the running game -- per Statcast: 39th in pop time; 27th in arm strength; 71st in exchange -- which leads us to give more credit to the Rangers' pitching staff for turning on the red light.

Andrew Heaney and Jon Gray were the Rangers pitchers most likely to have a runner take off against, as they combined for 35 of the 122 stolen-base attempts against Texas. We'll note that Gray, along with lefty reliever Will Smith, picked off a pair of runners to lead the Rangers staff. Heim, by the way, did succeed on a pickoff attempt of his own. He attempted 19 backpicks overall. 

This too appears to be a strength-on-strength matchup. It'll be interesting to see which side prevails. 

3. The bullpens

Here's the wild card that might determine the series. The Rangers and Diamondbacks both had below-average regular season bullpen ERAs. 

This is where we stress that those numbers aren't always an accurate representation of a team's playoff bullpen. Teams approach the postseason differently, and one product of that is how much more aggressive they are in deploying their best relievers. That, in turn, can radically shift what a bullpen looks like in October versus what it looked like from April through September.

To demonstrate what we mean, take a look at the table below. In both cases, we've compared the club's regular season bullpen ERA to what it would have been if the numbers included only the relievers who have appeared in half of their postseason games. For the Rangers, that includes Jose Leclerc, Josh Sborz, and Aroldis Chapman; for the Diamondbacks, that includes Paul Sewald, Kevin Ginkel, Ryan Thompson, Andrew Saalfrank, and Joe Mantiply. 

Team	Overall	Circle of Trust	Net
Rangers	4.77	3.97	0.80
Diamondbacks	4.22	2.85	1.37

Not only does Arizona manager Torey Lovullo have a wider circle of trust, he also has a much better bullpen situation than the D-backs' overall regular season figure indicates. No wonder the Diamondbacks felt comfortable using a bullpen game during the NLCS -- they may be nicknamed the Chaos Snakes, but their best relievers have a way of keeping things calm.