Ryan Zimmerman, left, may go back to third base when Bryce Harper returns even though Anthony Rendon, right, has played well there. (Jonathan Newton/The Washington Post)

The clang off the back of the bullpen Friday afternoon at Nationals Park was another no-mistake reminder. Bryce Harper’s injured left hand is healthy enough for him to swing a bat — and swing ferociously. For the second straight day, he took batting practice. For the second straight day, it was a don’t-miss-it show, with balls sprayed to previously unseen parts of the yard.

Harper’s return — around July 1, give or take a few days — doesn’t amount to a problem for the Washington Nationals, whose offense has been middling in just about every category through the first half of the season. As we keep hearing, these things have a way of working themselves out.

But it does bring up problems that, until this point, the club has been able to shrug off. Namely, where does everybody play when the opening day left fielder returns — well, where, exactly?

“It’s a question that has to be answered,” Manager Matt Williams said Friday, “and we’ll answer it when the time comes.”

The time is coming — and fast. And the presumptive solution may not work.

“I’m willing to do whatever,” said Ryan Zimmerman, the erstwhile third baseman who played his 16th game in left field — Harper’s spot — Friday against the Braves.

“Willing,” in this case, should not be confused with “wanting.” So what seems to be an easy solution — Harper to left, Zimmerman back to third, Anthony Rendon back to second and Danny Espinosa (and his .292 on-base percentage) back to the bench — may in fact be difficult.

It may also not make much sense.

“Anthony’s a hell of a third baseman,” Zimmerman said. “Having him at third, Danny’s defense at second, I think gives us the best chance to win.”

Translation: I’ll go back to third if you make me, but you’ll have to make me. And why would you do that anyway because it’s not our best lineup?

Let’s identify the nailed-to-the-floor, immovable objects first. Rendon, a third baseman in college who debuted in the majors at second because Zimmerman was entrenched at third, must play every day. Same for Zimmerman — or close to it — because he is a known quantity: a batting average between .275 and .307 and an on-base-plus-slugging percentage between .774 and .899 each season since 2008. He also happens to be due $100 million over the next six seasons.

Add Harper. The Nationals have already missed him for 50 of their 72 games. Regardless of any sentiment there might be that Harper must “earn” his way back into the lineup, he is their most dynamic offensive force. He must play every day, too.

“We want to have our best lineup, our best nine guys in there on any given day,” Williams said. “So that’s part of the evaluation, part of the decision that has to be made on any given day when Harp is ready.”

But part of the evaluation has to be why Zimmerman ended up in left in the first place. Consider, too, what it would mean to bring him back to his old spot.

“Moving out to left field, it’s been nice,” Zimmerman said. “I’m not gonna lie. I really like it.”

Zimmerman’s shoulder is simply not fit to play third base every day, and he knows it. For two years, it made every play a disaster-in-waiting. Since he returned from a broken thumb June 3, he has performed admirably in left. “He’s been fine,” Williams said.

But he can’t throw, not with the velocity and precision needed from a third baseman. Twice on Thursday night against the Braves, he heaved the ball in the general vicinity of the cutoff man. Neither time did the Braves take an extra base. No damage done. Had those throws been from third? Look out. Tellingly, he has not taken grounders at third, either.

So why would Zimmerman return to third and all that anxiety?

“Coming into this year, they planned this team around me making it through this year at third base,” Zimmerman said. “So it’s tough for me to say I don’t want to do it. It’s kind of putting them in a bad situation.”

But consider the other options.

When Denard Span arrived to play center before 2013, he brought a career .357 on-base percentage with him from Minnesota. In his one season plus two-and-a-half months in Washington, that’s dipped to .316. Yes, he has been hot enough lately (.310 average, .347 OBP, .469 slugging percentage) in his most recent 26 games before Friday) that benching him could seem odd.

But one month doesn’t make the player, and as much as Williams can be in denial about Span’s offensive play since he arrived here — he did not see him everyday in 2013, and he’s fine with what he has seen this year — there are some undeniable facts. This season, an average National League leadoff man carries a .327 OBP and a .722 OPS. Span’s numbers in the leadoff spot: .316 OBP, .715 OPS. Below average.

Keep him in for defense, then, right? Yes, he is the Nationals’ best defensive center fielder (though Harper played competently there as a rookie in 2012). Span seems like a classic center fielder — great jumps on balls both going in and back, a guy who covers tons of ground and makes life easier for both corner outfielders. Yet advanced metrics suggest that’s not the case. Span’s Ultimate Zone Rating, which takes into account range and arm for an outfielder, is actually below average — negative-3.4 where zero is average.

So that’s one potential swap: Harper in for Span in center, at least on most days, and everyone else stays where they are. And Span wouldn’t have to sit all the time. Jayson Werth is 35 and looks like he could use more than the occasional day off in right. Harper could play right on those days, with Zimmerman in left and Span in center.

But Zimmerman back at third? It’s not the simple solution. In fact, it complicates things.

“When it comes down to it, we’ll make a decision, I guess,” Zimmerman said. “I don’t know.”

Someone needs to know and soon. Yes, sometimes these things work themselves out. But when they don’t, someone must take charge of the situation and have a clear plan for what the lineup will look like going forward. Someone must work it out.