As we make the final turn into the home stretch of the 2021 MLS regular season, it's basically impossible to refrain from salivating over the Eastern Conference battle royale that awaits in the Audi MLS Cup Playoffs.

As has become standard in recent years, the road through the beastly East toward MLS Cup will be fraught with peril at every turn. Four of the current top title threats reside in the East, and that doesn't include 2020 Supporters' Shield winners Philadelphia. We will include the Union here for a look at each of the top five contenders to reach MLS Cup out of the East.

For each club, we'll play both advocate and devil's advocate to make a case for why they will and then why they won't reach MLS Cup. Get ready to be pulled in opposite directions five times, folks.

Why they will make MLS Cup

What isn't there to like about the Revs, who always seem to have all bases covered? Head coach Bruce Arena certainly knows how to navigate a team through the playoffs. They feature MVP frontrunner Carles Gil, but have the horses to keep on rolling while he sits out for an entire month at the same time other key cogs are away on international duty. They also have the clear best home record in the league and at this point, it would take a near-miracle to bounce them from the East's top seed. If penalties come into play, they have ace shot-stopper Matt Turner.

That's the obvious stuff and it's a lot, but it's also just the tip of New England's iceberg. The Revs can hurt you from out wide or they can punch straight up the gut. They can win strangled-off games where chances are at a high premium and they can win a wild run 'n' gun affair. On top of all that, this team just has that Blues Brothers "mission from God" vibe. You very much get the feeling they'd drive an old police car through a shopping mall, foil Nazis at every possible turn and disrespect Aretha Franklin in order to give this club the MLS Cup title that has somehow eluded them for a couple decades.

Why they won't make MLS Cup

Please don't think I'm trying to get supernatural on you, but there is definitely something extremely dangerous about entering the playoffs as the East's top seed. It could just be a long season catching up with teams in a hotly contested league, either through key injuries, opposing coaches getting wise after multiple meetings, or some such factor. Or it could just be witches and warlocks, it's hard to say.

Whatever the reason, there's no escaping the fact that, since 2008, only one club (the nigh-unstoppable Toronto FC side of 2017) that topped the East in the regular season has made it to MLS Cup. In fact, eight (!!!) of those 12 Eastern No. 1 seeds were dumped out of the playoffs at the first hurdle. And if New England go on to claim the Supporters' Shield, they'd only add another layer of curse to this danger cake – since 2004, only three regular-season champs have reached the postseason title match.

If none of that worries Revs fans, there's also a very middle-of-the-road 2-2-2 record against the four teams listed below so far this season.

Why they will make MLS Cup

It may seem daft to play the old "we haven't yet seen the best of them" card for a team that stands second in the East despite having at least one game in hand on a majority of the conference, but... well... I'm here to tell you we haven't yet seen the Lions' best.

The main reason for that is their spear has been missing a tip for most of the year, but Daryl Dike is finally fit and we now know he's definitely sticking around until winter. What's more, Alexandre Pato seems to be getting fit in time for the stretch drive. This is a very different side with them available, and other teams should rightfully be scared of a fully fit Orlando City attack.

Why they won't make MLS Cup

Flipping a switch is easier said than done, and Orlando City kind of need to do that to reach top gear. Talisman Nani has been dinged up of late, and one always has to worry about what has become an annual fall swoon that tends to start, oh, about now. Bookend threat Chris Mueller has struggled most of the year, and hasn't produced a goal or assist in almost two months.

Along with Dike and Nani, engine room keys Mauricio Pereyra and Sebastian Mendez are fighting off knocks, and it's unclear when Uri Rosell will return. Add it all together, and a lot of things need to go right for us to have the chance to see this club's best. Besides, even if they get it all together, New England's home field has been a house of horrors (0-4-1 with a -12 goal differential) for Orlando City.

Why they will make MLS Cup

Some things remain the same. The Music City bunch still boast one of the stingiest defense in the leagues, which is led by Walker Zimmerman, a guy who proved last year he has a "playoff god mode" level. They're backed by a "typically make the stops he should" netminder in Joe Willis, and head coach Gary Smith also has a deep and impactful midfield crew that limits final third incursions and springs dangerous counters. All this goes a long way toward explaining how Nashville have only lost twice this season (no other team has fewer than four defeats).

What has changed to make Nashville a real threat to win the East is that Smith now has strikers who'll actually finish off their fine approach play by putting the ball in the back of the net. Led by the scorching hot CJ Sapong, the second-year club has a center forward stable that's combined for 12 goals this term. Add that to the goal-dangerous playmaking duo of Randall Leal and Hany Mukhtar, and you have the third-most potent attack in the East. Working in concert with a defense that concedes the second-fewest goals per game in the league, that's more than enough to get them to the big dance.

Why they won't make MLS Cup

No side is perfect, and all that good stuff mentioned directly above comes with some troubling caveats. Let's start with the obvious. While Nashville have only dropped two games in regulation, they've also racked up a league-high 11 draws (or three more than their victory total). Their games tend to be tight and tense, and clubs usually can only come out on top in these types of contests for so long.

Why so many draws? Well, there's the inconsistent manner in which they start games. Seven of Nashville's 20 goal leaks have come inside the opening 20 minutes, and they've dug themselves four two-goal holes on the term. They've also had some issues closing out games, dropping points from a second-half winning position four times. As good and improved as the team has been, Nashville still have some edges to smooth out before the postseason arrives.

Why they will make MLS Cup

You can take the underlying numbers, the overlying numbers and everything in between, and they'll make one believe this team is primed for an earnest MLS Cup chase. The Cityzens comfortably lead MLS in expected goals (xG) differential per 90. It's no mirage, as NYCFC also stand above all in real goal differential even though they have games (plural) in hand on more than half the league.

Even if you don't feel like stat-nerding, there's still plenty of evidence to consider NYCFC a title threat. The roster boasts grade-A talent at nearly every position from front to back, and many of those players have been together for a few years now. Their defense is only becoming stronger as the season progresses (just four goals allowed in the last eight games), the attack scores first more often than not and the whole team has the ball skills to constrict any game with possession.

Plus, the club's very own postseason landmine side Toronto FC will almost certainly be watching the playoffs from home this year. All in all, this will be one tough nut for any team to crack.

Why they won't make MLS Cup

Right off the top, it would be hard to argue against the idea that NYCFC are the league's top postseason disappearing act. The Bronx boys have finished no worse than seventh in the Supporters' Shield table over the last five seasons, yet have managed to win a grand total of one playoff round over that span. They need a hoodoo-snapping deep postseason run, and those aren't easy to come by in the East.

Setting that redemption mountain to climb aside, there is also one extremely important concern on a micro-level: their striker situation. Heber recently returned to training after a year on the shelf with a major knee injury, but there's no telling how useful he will be over the remainder of this campaign. Regaining top form after ACL surgery typically takes some time, which means Valentin Castellanos is quite likely their only No. 9 hope in 2021. Even with his recent hot streak, Taty has been the most wasteful center forward in MLS this season. If his goals dry up or he becomes unavailable for some reason, this team is in big trouble.

Why they will make MLS Cup

I hate to do this, but we're going to have to deal out that "we haven't yet seen the best of them" card again. The Union emptied the tank physically and emotionally to bring home the Supporters' Shield last season, and then were unceremoniously dumped out of the playoffs in the first round. Jim Curtin is a smart guy, and he undoubtedly learned something from how that all played out.

Of course, that's not all Philly have in their favor. Curtin has a very deep squad that is well-drilled in tactics that MLS opponents don't see all that often these days. They are as deadly on set pieces as anyone. When all else fails, they have Andre Blake in goal to save their big-game bacon. Despite a lot of factors conspiring to cause them trouble this season (two Best XI departures in the offseason, an early Champions League fixture crunch, key elongated international absences, etc.), and yet they still hold a winning record. It's also worth noting they're the only challenger on this list with a winning record at New England (6-4-4 in league play, including 2-2-1 from the last five visits).

Why they won't make MLS Cup

I hate to do this, but we're going to have to bring up that flip-switching issue again. Philadelphia don't just have the clear worst record among the East's top five teams so far this season, they have it for good reasons. The Union have the lowest xG total of the five, as well as the highest expected goals allowed (xGA) total of the five. And these aren't just numbers; the eye test matches up.

A deeper dig into the Union's season unearths several specific problems. Among the East's current big five, they have the lowest passing percentage, put the least shots on goal per 90 by a wide margin and have the most discipline issues. Winning in the playoffs requires a winning streak, and Philly have managed but one thus far this season. While they fare well in New England, they're also a combined 2-8-4 away to the other three and will probably need to take a route through one of those places. Finally, for all his great success with the club, Curtin has to date advanced the Union exactly one MLS Playoffs round in five tries.