I'd argue that the two most important players for the (still)-first-place-in-the-East Philadelphia Union are C.J. Sapong and Vincent Nogueira. Or, I guess, "were" Sapong and Nogueira, since Nogueira is now a former Union player following his departure from the club for personal health reasons late this week.

Here is what my colleague Andrew Wiebe wrote on Friday afternoon:

[Nogueira] wasn’t just a box-to-box terrier. He was the Union’s deep-lying playmaker. He was their metronome, a safe outlet in possession who was precise and cutting once he received the ball. Oh, and he scored the occasional goal, too.

Here is what the lack of that looks like in one clip, taken from Philly's 3-2 loss at NYCFC on Saturday:

Warren Creavalle and Brian Carroll are both good MLS players, and both have been extremely effective for long stretches this season. But neither have Nogueira's ability to A) get to the most important "fulcrum" spots on the pitch early, and B) make quick, incisive decisions with their distribution.

One of the fundamental questions to ask about a soccer team is "How do you get the ball from the back to the front?" For the Union without Nogueira, the answer (in the first half anyway) was, "you don't."

This is brutal:

Union's passing in the middle third w/o Nogueira in #NYCvPHI. Nightmare - zero penetration. h/t @StatsZone pic.twitter.com/uXld3Rj9G8 — Matthew Doyle (@MLSAnalyst) June 18, 2016

The Union played square and without ideas, which has usually been the case over the last two-and-a-half years when Nogueira's been out. And in this one, his absence was compounded by the absence of Sapong, who missed the game with an ankle injury. Rookie Fabian Herbers was an energetic replacement, but he lacks Sapong's ability to win and control long balls, and then turn that into possession.

As one astute twitterer put it at halftime: "No Nogueira to pass through midfield, no Sapong to just bypass it. No more Union offense." He finished with the frowny face emoji instead of the poo emoji.

The good news for Philly? With the second-half additions of Roland Alberg (for Creavalle) and Ilsinho (for Chris Pontius), things kinda sorta changed. Alberg isn't the kind of game-conductor that Nogueira is from central midfield but he's expert at finding spots between the lines to get open, which provides easier opportunities for distribution from Carroll and the Philly fullbacks. Ilsinho, meanwhile, constantly dropped back to receive the ball, presenting yet another useful outlet. The 4-2-3-1 changed to a 4-1-4-1, and it worked so well that the Union were probably unlucky to come away empty handed. A point wouldn't have been unfair because the second-half adjustments were that good.

That said, I'm not sure how much of the game's shift came from the good changes by Jim Curtin, and how much from the effect of the game state -- NYCFC clearly took the foot off the pedal once they went up 3-0.

For now, though, the Union still have a grip on first-place. How long they keep it will be determined by how quickly they find an answer to this unexpected and potentially season-shaping departure.