Given that the surprising Marlins are on track to record the best record in one-run games in the Modern Era (currently 19-5), one might assume that the biggest reason is a lights-out bullpen getting things done in crunch time.

But that’s not exactly the case. The Marlins’ relief corps ranks just 14th in MLB with a 3.90 ERA and has struggled lately to lock down games, with a key three-game series against the NL East-leading Braves looming over the next three days.

Still, though, there are plenty of reasons to think this group is better than those basic numbers would indicate -- a good sign for Miami’s continued one-run success, and for its playoff hopes.

Here’s a look at the Marlins’ key relievers, what makes them statistically elite and what the club can expect from them for the rest of 2023.

Cast of characters

By expected weighted on-base average (xwOBA) -- a metric that takes into account quality of contact, strikeouts and walks -- the Marlins have seven of the top 50 relievers in baseball and five of the top 22, entering play Friday.

Regular closer A.J. Puk might be the only relatively big name of the bunch. The sixth overall pick in the 2016 Draft, Puk was acquired from Oakland this offseason for JJ Bleday. His Baseball Savant page is redder than a South Florida beachgoer without sunblock, with Puk ranking in the 90th percentile or better in average exit velocity, xwOBA (97th percentile), expected slugging percentage (92nd), barrel rate (95th) and walk rate (97th).

The rest of the Marlins’ bullpen? These names might be new to you, but some of their numbers are just as impressive. Credit general manager Kim Ng for putting together a talented -- yet under-the-radar -- relief crew.

Dylan Floro, acquired from the Dodgers in February 2021 for Alex Vesia and current Minor Leaguer Kyle Hurt, owns the 10th-lowest barrel rate of any qualified pitcher. Another ex-Dodger, JT Chargois, was traded to Miami from the Rays in November 2022. His xwOBA of .246 ranks him 20th in the Majors.

Lefty Andrew Nardi, who posted an unsightly 9.82 ERA in 14 2/3 innings as a rookie last season, has become another standout reliever. The 24-year-old -- a 16th-round Draft pick in 2019 -- is in the 97th percentile for average exit velocity and in the 94th percentile in hard-hit rate. After two big outs Thursday against the Red Sox, Nardi has 46 strikeouts in 35 1/3 innings this season, and his ERA is just 2.55.

While Nardi’s strikeout rate of 32.9% is impressive, a pair of his fellow relievers have him beat. Now in his third season with the Marlins, right-hander Steven Okert has fanned 37.6% of the batters he’s faced -- 38 of them in 27 innings. That ranks eighth in the Majors among relievers who have pitched 20 or more innings this season -- ahead of even Josh Hader.

Right behind Hader is Marlins lefty Tanner Scott, acquired in a trade with the Orioles in April 2022. Scott has 56 strikeouts in 39 innings this season and a 35.9% K rate. He’s also in the 99th percentile in hard-hit rate, the 96th percentile in xwOBA and the 98th percentile in xSLG.

That’s a lot of numbers to say this: The Marlins’ bullpen might not have much name recognition, but it has a lot of talent.

Pitching to contact

Despite the promising numbers above, the Marlins’ bullpen doesn’t feature a ton of high-velocity hurlers. Miami, in fact, is one of nine teams whose relievers haven’t thrown a single pitch 100 mph or faster this season.

Nor do Marlins relievers as a whole strike out a ton of hitters -- just 24.9%, 12th among Major League bullpens. Their walk rate (8.9%) ranks eighth in the Majors.

What the Marlins’ bullpen does better than any other is limit hard contact. Miami relievers are holding opponents to an average exit velocity of 87.2 mph -- 1.4 mph lower than the league average on batted balls and tops among Major League bullpens.

Lowest avg. exit velocity allowed by relievers, 2023
1. Marlins: 87.2 mph
2. Yankees: 87.5 mph
3. Padres: 87.6 mph
4. Mariners: 87.8 mph
5. Rays: 88.1 mph

Along those lines, Marlins relievers have also allowed the lowest percentage (32.5%) of hard-hit balls (95+ mph). They have the third-lowest sweet-spot percentage (30.1%) and are tied for the sixth-lowest barrel rate (6.7%).

But Miami isn’t seeing that success translate into easy outs. The BABIP (batting average on balls in play) against the Marlins’ bullpen is .308 -- fifth-HIGHEST in the Majors. The Marlins’ defense (23rd in the Majors by Outs Above Average) surely plays a role in that disparity, but some of the issue is likely just bad luck. Whatever the cause, the Marlins’ bullpen has suffered from MLB’s largest gap between its actual and expected results, tied for second in xwOBA but ranking just 19th in wOBA.

Largest xwOBA-wOBA gap by RP, 2023
1. Marlins: 21 points
2. Rockies: 21 points
3. Phillies: 13 points
T-4. Giants: 5 points
T-4. Athletics: 5 points
T-4. Mariners: 5 points

Need an example? On June 23 against the Pirates, Puk took the mound in the ninth inning aiming to protect a 1-0 Marlins lead. Josh Palacios greeted him with a line-drive single measured at just 70.9 mph, and Andrew McCutchen followed him with an infield hit clocked at 66.6 mph. After both runners scored, Tucupita Marcano added a third run with an 80.2 mph hit off Floro to drive in another run.

None of the three balls was hit hard, but all three contributed to a big inning against the Marlins ‘pen.

What comes next

There’s no guarantee that the Marlins’ luck will turn.

It’s entirely reasonable Miami’s bullpen will continue its struggles -- or simply fail to sustain its elite suppression of hard contact. Additionally, the Marlins’ lack of elite strikeout stuff opens the door to bad outcomes on balls in play, especially with a below-average defense.

But signs point to improvement on the horizon -- and that could do wonders for a surging Miami ballclub.

After sweeping the Red Sox in Boston, the Marlins remain in second in the NL East, six games back of the Braves -- well within striking distance. They have sole possession of the NL’s top Wild Card spot and have a three-game cushion in the loss column over the Phillies, the best team currently out of the playoff picture.

While Luis Arraez, Jesús Luzardo and Eury Pérez have been big parts of Miami’s success this year, an improved bullpen could maintain -- if not improve -- the Marlins’ standout record in close games.

And when it comes to the postseason, well, a lockdown bullpen can make all the difference.