The question facing Victor Robles is whether he can play with all the muscle, the weight it adds to his frame, the two biceps that make his shirts look like children’s clothing. And his latest attempt to untangle this will come in winter ball in the Dominican Republic.

Robles, the Washington Nationals’ 23-year-old center fielder, has joined Águilas Cibaeñas. So instead of shutting down this month and next, he will test his arm, bat and speed on the fields of his native country. The Nationals are counting on it going well. In 2020, his second full season in the major leagues, Robles regressed at the plate and, more surprisingly, on the base paths and in center.

He had been a Gold Glove finalist who finished sixth in rookie of the year voting, a sign that he may ascend up the batting order and meet the hype of his arrival. But Robles struggled with one noticeable difference: Manager Dave Martinez noted that he gained 15 pounds of muscle while working out during the coronavirus pandemic. Martinez saw that impact Robles’s speed and flexibility, accounting for the poor results on defense. His offense, however, is a harder puzzle to solve. Numbers and observation point to Robles starting poorly and, in turn, chasing results instead of staying patient, something the Nationals have stressed with him since he debuted in 2017.

The recipe brought little good.

“Sometimes the best thing you can do is see pitches,” Martinez said of Robles in September, adding then that he’s “not awful right now” and still has much room to grow. “Try to get the ball in the strike zone. Know which balls you can hit hard and wait for that one pitch. I’ve been there before. You start trying to swing your way out of it. Sometimes you start chasing way out of the zone, and obviously he’s done that quite a bit.”

The most concerning evidence is that Robles swung at the first pitch in 41.3 percent of his plate appearances, well above the MLB average of 28.3 percent. That can be a solid strategy for some hitters. But it’s a less encouraging sign when the final numbers are a .293 on-base percentage, 53 strikeouts to nine walks, and just 37 hits in 52 games.

And though Martinez mentioned Robles chasing pitches, the numbers don’t reflect any shift in approach. His rate of swinging at pitches outside the strike zone was similar to his rate in 2019, a much better offensive season for him. He saw a similar distribution of fastballs and breaking pitches in each season. His swing percentage — accounting for how often a batter swings — hardly changed.

Yet his contact was down, and his production sagged. That hints at poor timing and worse pitch recognition. Or, as Martinez often suggested, Robles also had trouble adjusting to his new physique. The manager was quick to say that Robles was not out of shape. He frequents the gym in normal times, always ending game nights with a lift that leaves him sweating before interviews. But he was slower, he slipped on defense, and he generated very limited power in the box. Each development, backed by advanced statistics, made it hard to see what all the added muscle is for.

In 2019, Robles’s average sprint speed — measured by Statcast in feet per second — was 29.3 with 62 “bolts.” Bolts account for any time a runner is moving above 30 feet per second, and 62 was the fourth-highest total in baseball. In 2020, Robles’s average speed was 28 feet per second, and he finished a shortened year with just four bolts.

He lost a lot of his quickness. Martinez explained on multiple occasions that his first step was slower in the outfield, leading to a handful of balls dropping in shallow center. In another area of sharp regression, Robles led all outfielders with 23 defensive runs saved in 2019. A year later, with the metrics warped by the condensed schedule, Robles was tied for 45th among outfielders with negative-4 runs saved and only preserved the perception of his strong defense with a handful of outstanding plays.

Then there was a concerning trend at the plate. Robles put 118 balls in play in 2020. Only 27 of them traveled 95 mph or faster, putting him in just the second percentile of hard-hit percentage in the majors. His average exit velocity was a quiet 82.2 mph, good for the bottom 1 percent of MLB. It’s tough to hit well when hitting that soft.

“I know he’s trying really hard,” Martinez observed in September. “Too hard sometimes.”

Martinez was willing to see whether Robles could adjust to the added muscle. “We don’t talk to him about necessarily the weight gain,” Martinez said. “We talk to him about his flexibility, his speed, agility, his first step. I mean, stuff like that. If he feels like he can carry the weight, then we really want him to really hone in on his flexibility and his first-step quickness.”

As this past year wound down, Martinez seemed torn on Robles playing winter ball. On one hand, the manager recognized the benefit of Robles seeing more pitches and getting more reps in the outfield. On the other, Martinez felt that Robles, though young and spry, may benefit from another break. With the promise of a shuffled lineup next spring, the Nationals could really use stark improvements from Robles’s spot in the order, whether it’s seventh, eighth or near the top.

Offseason at-bats with Águilas Cibaeñas now bring the chance to fine-tune out of the spotlight. Robles’s next steps will depend on how that goes.