No one player can win or lose a championship: This isn’t the NBA. Every roster spot is its own cog, every matchup is just one man against another man -- you can’t hit a six-run homer. Neither Ted Williams nor Barry Bonds, we remind you, won a World Series.

But that doesn’t mean one player can’t make all the difference in a series. Sure, Corbin Carroll and Corey Seager, the best player on each of the teams in this World Series, need to perform for their teams to win. But it’s the other guys, the ones who don’t show up in every game promo, who will be the players on which this series hinges.

Here’s a look at four players on each team (eight total) who could prove the most important in this series, and we’ve broken them down into four categories.

CATEGORY 1: THE STARS

Marcus Semien, 2B, Rangers
It has become axiomatic to say things like “Marcus Semien is so underrated,” and while that’s partly true, the guy has finished in the top three of MVP voting twice, and he’s going to get votes again this year: He can’t be that underrated. But for a team built with top-shelf stars, often brought in via free agency, Semien, for all his success in the regular season, has been a near-zero this postseason. He was 1-for-9 against Tampa Bay, 3-for-14 against Baltimore and 6-for-29 against the Astros. Semien had 29 homers and 14 stolen bases this season. He doesn’t have a single one of either this October. That’s a full month that this MVP-level player has struggled. The Rangers have a lot of other talent, but Semien is supposed to be the straw that stirs the drink around here. Getting him going is imperative.

• D-backs vs. Rangers World Series Game 1 FAQ (Friday, 8 ET, FOX)

Christian Walker, 1B, D-backs
Walker was once known as the guy who had to follow franchise legend Paul Goldschmidt at first base. But for the last two years, he’s been nearly Goldschmidt’s equal, and is fourth in WAR (per FanGraphs) among first basemen in that span. That’s ahead of such bold-faced names as Pete Alonso and Vladimir Guerrero Jr., to name a couple. But while his stellar defense has remained this October, his bat has vanished. Walker led Arizona with 33 homers this season. He had one homer against the Dodgers in the NLDS, but he was 2-for-9 in the series and then struggled in a big way in the NLCS, going 2-for-22. It is very much to the D-backs’ credit that they’ve reached the World Series despite one of their most reliable power hitters giving them almost nothing. But it’s tough to find a path for them to win this series that doesn’t feature Walker getting back to normal.

• Ranking the 10 best bats in the World Series

CATEGORY 2: THE STARTING PITCHERS

Max Scherzer, RHP, Rangers
Scherzer’s first start this postseason, against the Astros after more than a month on the injured list, made you wonder if you would see him again this postseason, or at least have him be relegated to bullpen duty. But his second one turned out to be a start in a Game 7 winner. Sure, Scherzer was hardly the reason for that; it’s always nice when your team scores 11 runs for you in a clinching game. But Scherzer, even though he only went 2 2/3 innings, did look sharper, even if the numbers didn’t necessarily show it. The Rangers (probably?) won’t score 11 runs in every one of his starts, but they don’t need him to be his old-school ace self either. Can he work himself up to, say, five innings pitched, two runs allowed or so? That’s far below his historical standards. But it would be exactly what the Rangers need. And who knows? Maybe he still has one of those vintage Max starts left in him.

• D-backs, Rangers took similar paths to improbable World Series matchup

Brandon Pfaadt, RHP, D-backs
To look at Pfaadt’s regular-season numbers is to want to immediately look away: 3-9, 5.72 ERA. More hits allowed than innings pitched. Twenty-two homers given up in just 96 innings. All sorts of short, ugly outings. But this was the No. 59 prospect in baseball coming into this season, a guy who led the Minor Leagues in strikeouts last year. The Diamondbacks knew he’d come around eventually. He has come around, of course, at the perfect possible time, giving up five runs in four postseason starts, all D-backs wins. The Rangers have a lot of rotation depth, and the D-backs don’t: Heading into the playoffs, it was Zac Gallen, Merrill Kelly, cross your fingers for Pfaadt and then … bullpen game? But Pfaadt has been, amazingly, their ace in October. If he keeps this up -- and this isn’t a fluke, this guy has great stuff -- the D-backs may be able to match these Rangers, rotation-wise.

• 'What are we doing on our couches?' Pfaadt brothers road trip for Game 7

CATEGORY 3: THE RELIEVERS

Josh Sborz, RHP, Rangers
The Rangers have many options in their rotation, almost too many options, but when it comes to relievers they trust, they have José Leclerc and … then Sborz. That’s probably it. Aroldis Chapman’s surface-level numbers have been much better than his underlying metrics, and when you watch him pitch, you can’t help but suspect a Craig Kimbrel-esque reckoning is coming. The Rangers can see that as well as you or I can, which is why they avoided using Chapman in Game 6 of the ALCS, which was tight until Texas put up five in the ninth. This all points to the Rangers relying heavily on Sborz in the late innings. You can tell Bruce Bochy would like to save Leclerc for the ninth if he can, which means Sborz is going to have to lock down the eighth -- and maybe even earlier. Leclerc will only get the chance to close games out if Sborz gives him that chance.

Joe Mantiply, LHP, D-backs
Much has been written about how the Diamondbacks lost 110 games two years ago, just how much ground they’ve had to cover, how far behind they truly were. Here’s another example of it: Last year, the D-backs were one of the teams that only had one All-Star, and it was a random relief pitcher you’d probably never heard of. A year later, that “random relief pitcher,” in a tight series, may be the most vital piece of a World Series-winning roster. With the (quite understandable) struggles of fellow left-hander Andrew Saalfrank in the postseason, the D-backs are going to rely heavily on Mantiply against key Rangers hitters like Seager, Evan Carter and Nathaniel Lowe late in games during stressful moments. Frankly, any game that’s even slightly close, we’re likely to see Mantiply in a game-saving moment. Get used to extreme closeups of his face: Some of the most tension-filled pitches in this series will be thrown by him.

• The unknown reliever who became the D-backs' postseason X-factor

CATEGORY 4: THE WILD CARDS

Jonah Heim, C, Rangers
The All-Star had two big homers in the ALCS, but the key for him in this series may be his arm. When the D-backs were at their best in the NLCS, they were running around like crazy, swiping four bases in both Games 6 and 7 without getting caught. They are 16-for-19 in stolen-base attempts this October on the heels of finishing second in the Majors in steals during the regular season. A large part of keeping that aspect of the D-backs’ game in check in the World Series will be Heim. The catcher has proven to be an effective controller of the run game throughout the year, but he’ll be tested regularly this Series. The D-backs will try to use every edge they can find against the Rangers, a team that has a little bit more top-line talent. The stolen base is one of their best tools to do so. Heim better be ready.

Tommy Pham, DH/OF, D-backs
Pham has never made an All-Star Game, was already 26 when he was finally called up, and is on his seventh Major League team. But the Trade Deadline acquisition -- who once finished 11th in MVP voting, if you can believe that, back in 2017 -- is a key hitter in the middle of the D-backs’ lineup. One who, when he’s hot, can carry a team. The 35-year-old is a famously streaky hitter, and while he struggled in the Phillies series, he was still hitting the ball hard and did have a huge homer in the second inning of Game 6.