VIERA, Fla. —

For several days, the spring training fields here have been filled with the Washington Nationals answers — their brilliant pitchers, waves of them. Now the questions have started to arrive, too — the Nats’ position players.

For an indisputably good team, the Nats face a lot of serious questions about key players with decisions that, in a few months, may ruffle feathers.

Can left-handed hitters Adam LaRoche, Bryce Harper and Denard Span hit southpaw pitching? They certainly couldn’t last year — .198, .214 and .223, respectively . Throughout their careers, neither LaRoche nor Span has suffered from this affliction. Was ’13 just an ugly abberation?

Harper will play every day, no matter what, but his rapid rise to the majors cut deeply into his time to learn how to cope with left-handers. His career slugging percentage against southpaws is actually 81 points lower than Stephen Strasburg’s career slugging mark against lefties. That’s a sparse-data fluke, but also a trend to watch. The Braves pushed phenom Jason Heyward to the majors quickly and he didn’t adjust to lefties until last season, his fourth full year at 24. You pay for skipping developmental levels.

Is Ryan Zimmerman’s arm accurate enough for him to remain at third base? He’s already arrived here to find a first baseman’s glove in his locker, a gift from Matt Williams. The manager says he just wants Zimmerman to give LaRoche an occasional day off at first base against lefties. And that is truly what he hopes.

“Does that mean I get to go play third?” LaRoche asked.

“Nope, can’t do it,” said Williams, who has a bond with LaRoche from their days together in Arizona.

But the hint is unmistakable, for both LaRoche and Zimmerman. At 34, LaRoche is coming off bone-chip surgery in his elbow, had trouble keeping his weight up last season, looked hopeless against many southpaws and tailed off at the end of the season. The tip-off to a career slide or just a blip?

“LaRoche is LaRoche. Write down .260, 25 homers, 85 RBI and great defense,” General Manager Mike Rizzo said. Naturally, LaRoche expects no less. “The years I’ve been healthy, the numbers have been there at the end of the season,” he said, “though it was not always pretty the way I did it.”

That’s Plan A. But, if there’s no improvement on ’12, you can be sure there are Plans B and C, perhaps involving Tyler Moore in a platoon.

Zimmerman, once a Gold Glove winner at third, won’t miss the significance of that first baseman’s mitt. It’s usually a symbol of baseball old age or immobility. Zimmerman still is just 29. Can Zimmerman’s arm, disturbingly wild at times the last two years, regain its accuracy? Was his problem primarily due to injuries or has the easy-play throw gotten in his head? The Nats are fanatical about improving their error-gushing ’13 defense. How patient will they be since Anthony Rendon’s natural position is third base?

“Zim’s arm was good by the end of last year, finally 100 percent,” Rizzo said. “He made some diving plays, bounced up to throw. He looks fine.”

New defensive metrics expose a Zimmerman problem that for decades might have stayed hidden. To cover for his weak arm he played so shallow for most of the year that many balls got past him. Ultimate Zone Rating placed him as the fifth-worst defensive player at any position in baseball.

That might seem like more than enough positions with a hint of instability around them. But Sunday, Williams reinforced a Rizzo remark that second base was now an “open competition” between Rendon, assumed to be an infield fixture in Washington for many years, and Danny Espinosa, who hit .158 last year, then batted .216 when sent to the minors.

Is this an honorable experiment to give Espinosa’s shaken confidence a full fair chance to reestablish his promising career? Even so, does it undercut Rendon after a solid .265 rookie year at a position he’d never played?

Williams has already had Espinosa in his office to explain, “I’ve been that guy.” At 26, Williams followed two fine years with an awful season in ’92, hitting .211 in September. Lost at the plate, his future was questioned. Yet the next five years, Williams was awash in Silver Sluggers and Gold Glove awards. He’s told Espinosa just to “be yourself,” stop worrying, use all his talents, including bunting, and play brilliant defense.

“He’s someone I can relate to,” said Espinosa, now 26. “I feel like I can be me when I play.”

All these spring permutations lead to exotic hypothetical solutions. Against lefties, why not bench LaRoche, put Zimmerman on first base, put Espinosa at second, provided he hits decently this spring, and move Rendon to third where he’d played for years?

“On paper, things like that look good. But with real players they don’t usually work,” Rizzo said. “You’re making multiple players learn multiple positions then switch back and forth. For me, I think you decide on your second baseman coming out of spring training and stick with him.”

So, you guessed it, Espinosa is going to be asked to play some third base on exhibition game days when Zimmerman goes to first base. Got all that?

Since regulars won’t report officially until Tuesday, it’s seasonally appropriate to emphasize that the Nats’ Plan A is gloriously free of such annoying questions.

“We like the team we have. We won’t be making any [trade] phone calls,” said Rizzo, who would, of course, answer his phone for the right deal.

In that just-the-way-the-Nats-planned-it world, LaRoche has his usual solid season, his stamina helped by days off when Zimmerman or Moore play first base. Span hits lefties the way he always has — except in ’13. Harper, just 21, stays healthy and raises all parts of his game, including coping with southpaws. Rendon wins the second base job, but Espinosa rediscovers his swagger and joins Nate McLouth, Scott Hairston and strong backup catcher Jose Lobaton on a deep bench. And Zimmerman simply plays third like Zimmerman once again.

Many teams, even in February, must concoct far-fetched, almost prayerful scenarios to imagine a team that is powerful in some areas and weak in none. The Nats, who led the NL in runs scored after July 22, the day they changed hitting coaches, don’t have to go to those extremes.

“We are not making decisions based on small 200-at-bat samples from last year against left-handed pitching or errors made when you’re playing hurt for us,” Rizzo said. “That’s how you make bad long-term decisions. We evaluate by the whole historical track record. This team has a lot of players with impressive well-established track records. We’ll trust that.”

When it’s 83 degrees without a cloud in the sky in Florida that qualifies as trenchant analysis. There will be 162 games to find out if it’s true.

For more by Thomas Boswell, visit washingtonpost.com/boswell.