In one of the most unexpected matchups in recent memory, the Rangers and D-backs will face off in the 119th World Series beginning on Friday at Globe Life Field in Arlington.

Of the many factors that have propelled these teams from 100-loss seasons to the World Series in record time, each team's bullpen performance this October has been key -- and a far cry from the bullpens each team saw in the regular season.

D-backs relievers finished below average by both ERA (4.22) and FIP (4.34) during the regular season, while the Rangers' bullpen had the seventh-worst ERA (4.77) and a bottom-10 FIP (4.45). That script has flipped in the postseason, with Arizona's bullpen posting a 2.94 ERA in 49 innings and Texas' relievers having a 3.72 ERA in 48 1/3 innings. With each game carrying more meaning, both teams have leaned on a smaller group of relievers for the bulk of their innings.

This begs the question: Who are some of these guys and how did they help play a major role in getting their teams to the World Series? Let's dive in.

D-BACKS

Ryan Thompson, RHP
10 2/3 IP, 2.53 ERA, 10 H, 8 K, 3 BB

A member of the Rays' 2020 World Series roster, Thompson was released by Tampa Bay on Aug. 16 this year. Shortly after, the D-backs signed Thompson to a Minor League deal, and he made his Arizona debut on Aug. 27. Nearly two months later, the sidearm-slinging righty has been the D-backs' most-utilized reliever in the postseason. In fact, his 10 2/3 innings pitched are the most by any reliever in the playoffs. With his funky release point, nasty sinker/slider combo and strong command, Thompson has produced a 72.2% ground-ball rate in the playoffs with a .641 OPS against.

Kevin Ginkel, RHP
9 IP, 0.00 ERA, 6 H, 13 K, 2 BB

You'd be forgiven if you didn't know much about Ginkel heading into the postseason. After dominating with nine scoreless innings through the first three rounds, he's certainly made a name for himself. Drafted three different times in college -- he didn't sign after the Giants drafted him in the 16th round in the 2014 Draft or after the Red Sox drafted him in the 26th round of the '15 Draft -- he ultimately signed the third time with Arizona after being selected in the 22nd round of the '16 Draft. Seven years later, Ginkel established himself with a superb regular season (2.48 ERA and 70 strikeouts in 65 1/3 innings) and a dominant postseason thanks to good command of an upper-90s fastball and wipeout slider.

Paul Sewald, RHP
8 IP, 0.00 ERA, 3 H, 11 K, 1 BB

Sewald is the most recognizable name in Arizona's bullpen as the closer and someone with a track record of high-level success for multiple teams. The Mariners signed Sewald after the Mets non-tendered him prior to the 2021 season and immediately saw him become a great late-innings weapon out of Seattle's bullpen. The Mariners surprisingly traded him to the D-backs this past deadline in exchange for Josh Rojas, Dominic Canzone and Ryan Bliss. The move has paid huge dividends in the playoffs, as Sewald has not allowed a run and posted a remarkable 11-1 strikeout-to-walk ratio in eight innings. Sewald's quirky release point has led to great results on a 92-96 mph fastball and elite sweeper.

Miguel Castro, D-backs
5 IP, 5.40 ERA, 3 H, 4 K, 4 BB

The trio of Thompson, Ginkel and Sewald have accounted for a whopping 56% of Arizona's bullpen innings. Next in line in terms of innings is Castro, who has quite the journey to get to this point. He's just 28 years old but is already with his sixth MLB team -- including his fourth in the last four years. After spending the 2021 season with the Mets and '22 season with the Yankees, Castro signed a one-year, $3.5 million deal with Arizona with a $5 million '24 option (which vested when he reached 60 innings pitched).

Joe Mantiply, LHP
5 1/3 IP, 5.06 ERA, 5 H, 4 K, 3 BB

The veteran lefty and 2022 National League All-Star has been a jack of all trades this postseason for the D-backs. Mantiply has pitched in seven of Arizona's playoff games with six of them coming in different innings. The lefty was the opener for Game 4 of the NLCS in Arizona and has also appeared in innings 3-8 at various points. It's a testament to the 32-year-old's perseverance that he finds himself in this position. Like Ginkel, Mantiply was drafted three times but didn't sign until his third try, with the Tigers in the 27th round of the 2012 Draft. After throwing just eight MLB innings before age 30 -- and undergoing Tommy John surgery in 2018 -- Mantiply has found a home in Arizona.

Luis Frías, RHP
3 2/3 IP, 2.45 ERA, 1 H, 3 K, 1 BB

Signed as an international free agent by the D-backs out of the Dominican Republic in 2015, Frías slowly climbed the ranks in Arizona's system before making his MLB debut in '21. After a tough '22 MLB stint (10.59 ERA and 2.36 WHIP in 17 IP), Frías had a much better time around in '23 with a 4.06 ERA across 31 regular-season innings. After pitching just once in the first two rounds, Frías made three appearances in the NLCS, allowing his lone run on a J.T. Realmuto home run in Game 5.

Andrew Saalfrank, LHP
3.1 IP, 5.40 ERA, 2 H, 2 K, 8 BB

Drafted in the sixth round out of Indiana in 2019, the lefty reliever dominated the upper levels of the Minors this year with a 2.53 ERA and 93 strikeouts in 64 innings. When promoted to the Majors in early September, he proceeded to not allow an earned run (two unearned runs) in his first 10 games. Saalfrank has appeared in eight playoff games but has thrown just 3 1/3 innings as a lefty specialist and struggled with command.

Slade Cecconi, RHP
2 IP, 0.00 ERA, 2 H, 1 K, 0 BB

Not included on the Wild Card Series or Division Series rosters, Cecconi was swapped in for infielder Jace Peterson for the NLCS roster. The 24-year-old pitched a scoreless inning with one strikeout in both of his appearances against the Phillies. Selected by the D-backs as the 33rd overall pick in the 2020 Draft, Cecconi made his MLB debut in '23 and made seven appearances (four starts) with a 4.33 ERA in 27 innings.

Kyle Nelson, LHP
2 IP, 4.50 ERA, 2 H, 1 K, 0 BB

Only Castro made more regular-season appearances (75) than Nelson (68), yet the lefty reliever has appeared in just two postseason games (both in the NLCS). Drafted by Cleveland in the 15th round out of Santa Barbara in 2017, Nelson reached the Majors in 2020 and appeared in 11 games with the Guardians across parts of two seasons. Following the '21 season, Nelson was claimed off waivers by the D-backs, who in turn led Arizona with 111 appearances from 2022-23.

Ryne Nelson, RHP
1 IP, 27.00 ERA, 7 H, 1 K, 1 BB

The other Nelson on Arizona's pitching staff, the right-hander has struggled mightily in his two postseason appearances. Nelson made 27 starts (29 games) for the D-backs in the regular season with a 5.31 ERA in 144 innings. Thought of as a potential option for starts in the playoffs, Nelson has strictly pitched out of the bullpen so far. The future is still bright for Nelson, who entered the year as MLB Pipeline's No. 6 D-backs prospect.

RANGERS

José Leclerc, RHP
10 1/3 IP, 4.35 ERA, 8 H, 10 K, 6 BB

Leclerc is one of the longest-standing members in the Rangers' organization and is the only player left from their 2016 postseason team (Martín Pérez was on that team as well but he spent the 2019-21 seasons with other clubs). Leclerc blossomed into a lockdown late-innings option until the pandemic (he pitched two games in 2020) and Tommy John surgery in '21 led to him pitching just two innings from 2020-21. Since returning in June 2022, Leclerc has once again established himself as a stellar reliever, taking over the closer role in the playoffs. Outside the home run he allowed to Jose Altuve in Game 5 of the ALCS, the 29-year-old has pitched quite well.

Josh Sborz, RHP
8 2/3 IP, 1.04 ERA, 2 H, 7 K, 4 BB

Sborz has been one of the unexpected bright spots in a bullpen that had major question marks heading into the postseason. While Sborz's 5.50 ERA in the regular season might not have been fully indicative of his skills -- his expected ERA and FIP were both closer to 3.50 -- he was nonetheless a major question mark earlier this month. After pitching extremely well in high-leverage spots this October, the narrative on him has shifted dramatically. A second-round pick by the Dodgers in 2015, the Rangers acquired Sborz from Los Angeles in a minor trade in February 2021.

Aroldis Chapman, LHP
6 1/3 IP, 1.42 ERA, 5 H, 4 K, 4 BB

The Rangers acquired the veteran left-hander in exchange for the talented Cole Ragans on June 30, well before the Trade Deadline in a move to beef up a bullpen that needed work. Chapman, 35, is nowhere near his prime anymore, but despite the ups and downs, he has been a useful part of the Rangers' bullpen. Chapman has appeared in seven postseason games and allowed just one run, on a Yordan Alvarez homer in Game 2 of the ALCS. After seeing his fastball velocity drop for several years, Chapman has seen that velocity come back and is averaging 99.8 mph on his fastball in the playoffs.

Cody Bradford, LHP
5 2/3 IP, 1.59 ERA, 4 H, 4 K, 0 BB

The 25-year-old lefty debuted for the Rangers in 2023, alternating between the rotation (eight starts) and bullpen (12 appearances). That's proved to be valuable in the postseason as Bradford has chewed up middle innings for Texas. It's also a feel-good story for Bradford, who grew up about 35 miles east of Globe Life Field in Aledo, and was drafted by the Rangers in the sixth round out of Baylor University in 2019.

Dane Dunning, RHP
4 2/3 IP, 7.71 ERA, 5 H, 5 K, 4 BB

Selected by the Nationals in the first round of the 2016 Draft, Dunning was traded with Lucas Giolito and Reynaldo López to the White Sox in December 2016 for Adam Eaton. Dunning underwent Tommy John surgery in 2019 and didn't debut until August 2020. Four months later, he was traded to Texas in the Lance Lynn deal. Since coming to the Rangers, he's made at least 25 starts a season with an ERA running between 3.70 and 4.51. He's appeared in long-relief outings in the postseason but could make a potential World Series start.

Martín Pérez, LHP
3 1/3 IP, 2.70 ERA, 4 H, 1 K, 1 BB

Outside of the 2019-21 seasons when he pitched for the Twins and Red Sox, Pérez has been with the Rangers' organization since he was signed out of Venezuela in 2007. Pérez debuted in 2012 as a 21-year-old top pitching prospect and spent the next half-decade as a reliable starter for the Rangers. Following his stint away from Texas, Pérez returned as a free agent in 2022 and was an All-Star in his first season back.

Chris Stratton, RHP
2 2/3 IP, 6.75 ERA, 2 H, 2 K, 2 BB

Stratton was the second player in the deal with St. Louis that sent Jordan Montgomery to the Rangers on July 30. After spending his first four seasons with the Giants from 2016-19, Stratton has bounced around with four teams since then (Angels, Pirates, Cardinals, Rangers). Stratton is set to hit free agency at the end of the season and could have a World Series ring to add to his résumé.

Will Smith, LHP
2 IP, 9.00 ERA, 2 H, 2 K, 2 BB

It's been quite a few years for the veteran lefty, who won the 2021 World Series with the Braves and the '22 title with the Astros. It could be his third straight year with a World Series ring, all with different teams. According to MLB.com researcher Sarah Langs, this has never been done.

Andrew Heaney, LHP
5 1/3 IP, 6.75 ERA, 6 H, 1 K, 2 BB

Two of Heaney's three postseason outings have been as a starter, but after his last start (three runs, two outs recorded), he could be back in the bullpen for the World Series. Drafted ninth overall by the Marlins in 2012, he pitched in just seven games in Miami before being traded to the Angels, where he spent the next half-decade. He was dealt to the Yankees at the Trade Deadline in 2021, signed as a free agent with the Dodgers for the '22 season and signed with the Rangers this year.

Jon Gray, RHP
1 IP, 9.00 ERA, 2 H, 1 K, 1 BB

Gray was the third big free-agent signing prior to 2022 behind Corey Seager and Marcus Semien, signing a 4-year, $56 million deal with the Rangers after spending seven MLB seasons with the Rockies. Across 2022-23, Gray was a reliable starter for the Rangers, pitching to a 4.05 ERA with 276 strikeouts in 284 2/3 innings. Had he not hurt his right forearm at the end of the regular season, he might have made several postseason starts by this point.

Brock Burke, LHP
1/3 IP, 54.00 ERA, 1 H, 0 K, 1 BB

Burke was left off the ALCS roster with the returns of Gray and Max Scherzer. It doesn't appear likely that he'll be on the World Series roster. Drafted by the Rays in 2014, Burke was traded to Texas in a three-team trade in '18 and has been an up-and-down reliever with the Rangers.