The Union have gotten to know the family of necessity and invention pretty well over the last few weeks, and they will spend this weekend in that same company.

Eight major players will be absent Saturday against FC Cincinnati (8 p.m., PHL17), a game that was rescheduled into this FIFA window because of the Union’s Champions League run. (The game was originally planned for Aug. 14, two days after the semifinal series opener at Club América.)

For the most part, the Union aren’t complaining about this. They certainly wouldn’t trade the Champions League run for one MLS game against the league’s worst team, and they knew all along that six players would be with their national teams this weekend: Andre Blake (Jamaica), Alvas Powell (Jamaica), Olivier Mbaizo (Cameroon), Jamiro Monteiro (Cape Verde), Dániel Gazdag (Hungary), and José Andrés Martínez (Venezuela).

In fact, that total would be seven players if not for Cory Burke’s ankle injury. He’d be with Jamaica otherwise, and we’d almost surely have seen in him Thursday’s World Cup qualifier against the United States.

But one player absence not mentioned yet has the potential to give Jim Curtin a real headache this weekend in Cincinnati. Kai Wagner will be out because of the red card he earned in Sunday’s win over Columbus, which could have a cascading negative effect on this game’s lineup. (And if he wasn’t suspended, he might have missed this game anyway because his wife just gave birth to their second child.)

There are two candidates to stand in for Wagner at left back, Matt Real and Leon Flach.

Real should be No. 2 on the depth chart in theory, but he hasn’t so much as made the bench for a game since Aug. 5. Coincidentally, that was the day after a writer for the league’s website reported the Drexel Hill native might be traded soon.

» READ MORE: Chris Albright leaves Union to become FC Cincinnati’s general manager

Flach might actually be No. 2 on the depth chart at this point. The Union knew he could play left back when they signed him in March, and he filled in at the position after Wagner’s ejection. But if he starts there against Cincinnati, the Union will be short at defensive midfielder because of Martínez’s absence.

“Leon, through the course of the season, has been asked to do a lot of jobs for us,” Curtin said this week. “He’s been excellent on the left side of the diamond; he’s proven he can play as the lone 6 [defensive midfielder] in our diamond, which is a pretty demanding spot to play — we ask guys to cover a ton of ground and deal with the other team’s No. 10; and then you’ve seen him, in Kai’s absence after the red card, with his ability to cover the left-hand side as an outside back.”

If Flach moves to left back, we might see a formation change. A 4-2-3-1 with Flach at left back or perhaps even a 3-4-3 with Flach at left wingback would make sense.

“We know Leon, wherever we put him on the field, he’s kind of a no-nonsense player that does his job, really executes,” Curtin said. “Which is a long-winded way of saying I’m not telling you where he’s playing.”

Well, OK. But we can guess this much for now: Alejandro Bedoya is going to have a lot of work to do no matter who else is out there. He’s probably going have to play the full game, which the 34-year-old has done less often lately, unless the Union can run up a big lead early.

That raises this question, and it’s one Curtin took this week: would surrounding Bedoya with a bunch of teammates who will do most of the running — say, academy products Jack McGlynn, Quinn Sullivan, and Paxten Aaronson — take some of the burden off Bedoya’s legs?

And is that calculus further affected by knowing that Nathan Harriel would start at right back if there’s a four-player back line? That actually might nudge Curtin toward a 3-4-3, with Flach on the left and Harriel on the right.

But that’s just a guess from here. It’s up to Curtin to put the puzzle pieces together and keep the Union on track to a playoff spot.

» READ MORE: Big games around the world to watch this weekend