For D.C. United, another double dose of mid-week games is not exactly welcome right now. Sunday's game was played in draining heat, and the Black-and-Red had to work hard to come from 1-0 down to win. They've already played more games than anyone in MLS: 18 games in league play plus 2 in the CONCACAF Champions League and 1 in the Open Cup edges out Montreal (20, with only 12 in MLS padded by 8 in the CCL and the Voyageurs Cup) and LA (19, with 1 in the Open Cup). This team does not need another game tonight.

Then again, this is a rather pleasant moment to be playing the Chicago Fire. Frank Yallop's side has lost 3 in a row in MLS play, conceding 8 goals in the process. They're at the foot of the Eastern Conference. Furthermore, they'll be missing Shaun Maloney - their most expensive player in an offseason defined by splurging - due to back spasms. David Accam - their most effective Designated Player - has a hamstring issue and will miss out as well. Rookie of the year candidate Matt Polster won't be there to break things up in his normal defensive midfield role either, as he's suspended for yellow card accumulation.

In other words, a bad Chicago team that still hasn't figured out a plan on how to defend without being comically open at the back is missing two key attacking components as well as their best player when it comes to protecting that mess of a back four. United has made a habit of kicking teams while they're down over the past year and a half, and the Fire are down.

If not for their previous match, I'd be expecting the 4231 we saw at RFK three weeks ago. Maloney wasn't around for that one either due to national team duty with Scotland, and Harry Shipp lined up centrally rather than on one wing or the other. However, they started in a 442 against New England, and over the years Yallop has shown a willingness to jump around formation-wise whenever Plan A isn't convincing him. The 4231 probably has an edge here, but that 442 is very much on the table. So, we'll talk about both, starting with the slight favorite.

We start from the back as always. Jon Busch has apparently fully supplanted Sean Johnson as Chicago's starter; he's less likely to hand United a goal via huge mistake, but at 38 and generously listed at 5'10", there are also saves he simply can't make. Where he's clearly superior here is his organizational ability. For a defense that sometimes looks like Jeff Larentowicz and three random dudes wearing red, that's important.

That might be a bit unkind to Eric Gehrig, who is an entirely capable defender when in reasonable form, but right now no Fire defender can be happy with how things are going. This team has given up 2 or more goals in 6 of their last 7 MLS matches, and their shutout was against Montreal before the Impact got into their current, winning form. It's not all their fault, of course, but they do have a tendency to come unglued when too many moving parts are coming at them. There are issues further upfield, but a lot of these goals have come via miscommunication, poorly timed marking exchanges, and over- or under-aggression.

Larentowicz is doing what he can, though he still looks like a defensive midfielder filling in. Chicago only has one natural center back on their entire roster, and Adailton is not a good one. The Brazilian journeyman has awareness issues, isn't that good on the ball, and generally gives off that "send your attacks my way" vibe. In this alignment, I think normal left back Joevin Jones will be used further forward, so Lovel Palmer - another player out of position in this instance - will fill in for him.

Jones, incidentally, has proven to be a pretty underrated goal threat when playing in the midfield for Chicago. He has elite speed and occasionally produces excellent pieces of skill to break through defensive layers. Yallop is likely aware of Sean Franklin's absence, so don't be surprised if the Fire feed the ball to Jones regularly if this is the formation they choose. If Yallop doesn't trust Palmer in the back, we could see former Houston striker/winger Jason Johnson get a start in this spot, which means a broadly similar threat in this role either way.

In the engine room, Chris Ritter is the most likely replacement for Polster. Ritter is less mobile than the player he's replacing, but more importantly he's less quick to realize when he needs to get moving in transition. There are times where Ritter looks glacial, but most of the time the problem is recognition rather than physical speed. Razvan Cocis has held down the #8 role for a bit, but with the Fire struggling this is a spot they could make changes at. There's plenty of depth: Michael Stephens could play here, and Victor Perez was on the books for a La Liga team in 2014.

Of course, Stephens is probably needed elsewhere, and Perez has become a complete afterthought in the Windy City. Instead, I can't help but wonder if Matt Watson is the better choice given Ritter's slowness. The Englishman is mediocre on the ball, but he's fast and has a real zeal for covering ground. I don't think it's likely enough to put him on the graphic, but it's something I'd consider if I were coaching the Fire tonight.

Shipp will be playing attacking midfield, and he's the biggest danger Chicago poses. Shipp roves around finding gaps wherever he pleases, and he has the skill to beat teams with his passes as well as on the dribble. In particular, United needs to prevent him from facing goal on the edge of the box. If - and sometimes this is a big if for the Fire - the runs arrive, Shipp will get the ball to them. It might be a chip, it might be a backheel, but it will get there and it will be clever. United's defense must be alert to the runs so that they can be in position to intercept these passes (or at least block off the runner), or there's going to be trouble.

On the right, I think Stephens more or less has to start if the 4231 is to be used. Kennedy Igboananike has made some appearances there, but he's looked more comfortable up front. Of equal importance is the fact that no other Chicago striker has been threatening lately; the point man pretty much has to be Igboananike right now, and without Accam or Maloney there's no way Shipp ends up on the right. So, back to Stephens: He's a smart player who uses the ball well and makes few mistakes, but he's not a particularly threatening player in terms of producing goals and assists. His job here will be to be an option for Shipp to play off of.

If Yallop prefers a 442, things differ a bit:

Here, Shipp ends up on a wing, which means Jones is more likely to play his customary left back role. Shipp and Stephens will cut in from the wings, while the amount of ground a two-man central midfield is left to cover means Watson's chances of playing go up. Or, Yallop could keep Jones on the left and offer two very different threats on the wings, where Jones will stay wide and run at his man while Shipp will drift inside. That'd mean Palmer is at left back, which makes the left half of the defense highly vulnerable. Like I said, it's a good moment to play Chicago.

If Yallop goes with two forwards, I expect Guly Do Prado to start ahead of Quincy Amarikwa. Yallop seems to want to get Guly on the field, and Amarikwa hasn't done much this season anyway (though he did score the 116th minute winner in their Open Cup win over Louisville City). If Guly plays, he'll drop off the front line and often ends up playing with his back to goal. It's a bit unusual, because he drops deep enough that he can be confused for a midfielder, which kind of defeats the point of being a back-to-goal target. Play tends to slow to a crawl when Guly gets on the ball as well.

Off the bench, Amarikwa will almost certainly come in regardless of scenario and offer his usual mix of hard work, physicality, quickness, and sometimes adequate technique. Mike Magee is a possibility to participate here, but it's impossible to say to what degree. If Chicago finds themselves needing a goal to get 3 points in the final 15 minutes, though, look for him to get in. Yallop has to gamble a bit right now to get points and stay with the race for playoff spots. Watson and Jason Johnson are also potential sub options, as is Greg Cochrane at left midfield or left back.