For a first-place team, the Mets have given their fans a thrill ride. However much it may lack last season’s sense of certainty, it’s beginning to promise a much happier ending. Keeping the drama stoked for more than five months already has been a fluid roster that has been cause for alarm all season long, forcing GM Omar Minaya and his staff to adapt and overcome all season long.

Perhaps even more reassuring is that fact that a month ago, the Mets were beginning to look especially desperate, having fallen to third place in the NL East after a four-game losing streak. Since that glum low point on August 3, however, they snapped off a 2-8 run that has propelled them back into first place, a solid three games up on the Phillies coming into this weekend’s head-to-head matchup. Every flavor of Baseball Prospectus’s Playoff Odds Reports already have the Mets as an 86% shot to wind up playing October baseball, almost all of that via their winning the division title. While last September’s debacle probably aborts any declarations that the Mets could put away their least-favorite foes, it’s clear they can put a big dent in the Phillies’ future right here and right now.

You might wonder, how did they turn things around? Because of injuries, they’re effectively without their initial tandem of starting corner outfielders; they’re down a closer; their best-hitting catcher’s out, and they can’t even count on starting second baseman Luis Castillo, only recently back from the DL. It may have seemed that the rotation has been a season-long piece of patchwork — as they had to go without Pedro Martinez early, couldn’t count on Oliver Perez for extended stretches, and now they’ve lost John Maine late — but they actually rate third in all of baseball behind only the loudly touted units in Wrigleyville and Milwaukee. Even this weekend, there’s cause for concern, because they may have to skip Martinez after his failure to loosen up during his last time out.

The key to the Mets’ resurgence has been a reliance on two of the oldest virtues in the game: a quality rotation and power at the plate. On offense, they’re slugging .448 since the break after delivering only a .403 team SLG before the All-Star Game. Carlos Delgado’s recent hot hitting has gotten plenty of attention, but equally important to Delgado’s eight homers and .486 slugging in the last month has been backstop Brian Schneider’s entirely unexpected five homers and .586 mark in that same stretch. Turning to the rookie tandem of Daniel Murphy and Nick Evans has given the Mets a .521 slugger in their last 30 days; for the sake of comparison, Moises Alou was projected to slug .504 before the season. While dramatic late-game comebacks always engender debates over whether anyone’s been “clutch,” they invariably devolve into arguments over whether clutch hitting is a repeatable skill or if it’s merely an adjective describing a well-timed hit. The Mets’ best clutch hitter on the season in terms of plating runners on base has been Ryan Church; he’s driven in a little more than 18% of his base runners, but he’s also at less than his best now. David Wright, Carlos Beltran, and the ever-surprising Fernando Tatis have all driven in more than 17%, all excellent marks. Whether it’s a matter of timing or clubbing, the lineup’s plating people.

Balanced against that, they’ve also been getting great work from their rotation. Johan Santana’s delivered six quality starts in six turns (winning three). Oliver Perez has also given them six in six, although one quality start was lost in the seventh inning. Rounding out the front four, Mike Pelfrey’s delivered five of six (with four wins), and Martinez’s given them four in six. Barring a team-wide spin back to the high-mound ’60s via the way-back machine, getting 21 quality starts through six in 24 games during their race to the division lead is a massive number of winnable ballgames. Power and a quality rotation — as it was for Davey Johnson or Earl Weaver — that’s a formula for victory.

The immediate problem goes beyond the struggles in the bullpen that the club has already tried to paper over during Billy Wagner’s absence: The danger is that losing Pedro for any number of starts mirrors the problem they’ve had finding a fifth starter since Maine started breaking down in July. Between them, Maine, veteran swingman Brian Stokes, and rookie Jon Niese couldn’t deliver any quality starts in the five they made to round out the rotation; the Mets offense delivered well enough to outscore the trio to win three of those five games, but multiplying that challenge by two in Pedro’s absence could make things a little exciting down the stretch.

This week’s pair of off-days (and another on Monday) affords Jerry Manuel at least some flexibility, in that he could bring Santana forward a day to take Martinez’s scheduled turn on Saturday. Advancing Santana — although he’d still be pitching on four days’ rest — improves the chances that he’s available later in the month, and it might help cue up the staff ace to be available for a tie-breaking game or to lead off an NL Division Series. Should things go well on Friday, it might also put the Phillies squarely behind the eight-ball on Sunday trying to avoid a season-killing sweep.

Picking two starters from among Stokes, Niese, Nelson Figueroa, or Brandon Knight sounds like a challenge demanding more big-scoring ballgames from the lineup, but with 12 straight games against the execrable Nats and Braves on the other side of this series with the Phillies, that might be doable. The Mets have put themselves in the driver’s seat because of what they did last month; they can put the Phillies away by taking this weekend’s series, and then squelching any spoiling by Washington and Atlanta. If that sounds increasingly possible, sometimes you’ve just gotta believe.

Ms. Kahrl is a writer for Baseball Prospectus. For more state-of-the-art commentary, visit baseballprospectus.com.