(Matt Slocum / AP) (Matt Slocum / AP)

For the two seasons prior to this one, the Nationals most frequently stationed Rick Ankiel and Bryce Harper in center field. There are few outfield arms that can generate more power than Harper’s, and the rifle attached to Ankiel’s left shoulder is one of them. Both could bring a stadium to its feet with one throw, and in Ankiel’s case he may not even have to throw a runner out.

Denard Span knows he cannot compete with the arm strength of his predecessors. “For me, I don’t have a plus-plus arm,” Span said. “If I was to grade my arm, I would say it’s average – sometimes above average, depending how good I feel.”

But Span, as he showed again last night, has learned how to make gunning down runners part of his elite defensive repertoire. In the second inning, Span fielded A.J. Pollack’s two-out single to center and threw out Martin Prado at the plate, preventing a run and ending the inning. The Nationals’ offensive surge the next inning made it easy to overlook, but Span’s throw was a hugely important early moment.

Span has three assists this year, two of them at the plate. He makes up for his lack of a high-caliber arm three ways. He aggressively charges the ball, thereby shortening the distance of his throw. He uses a quick release – one step, not a pronounced crow-hop. And he is accurate; his throw last night one-hopped into Suzuki’s mitt on the left half of the plate.

“If I can do that,” Span said, “I’m going to give myself a chance to throw out runners.”

Span’s throwing technique also includes a twist. After he rushed the ball and came up firing, he somersaulted after he released the ball, his effort to get everything he’s got behind the throw.

“I know if I flip over like that, the ball is going to be more on line,” Span said. “It lets me know I’m staying through the ball and finishing off my throw.”

Span assumes opposing advance scouts tell their third base coaches to test his arm. And, in fact, opponents have hit 20 singles to Span with a runner on second base this year. In all 20 instances, the runner tried to score.

Last year, the Nationals at times limited runs with intimidation alone. Per Baseball-Reference, Ankiel had 14 chance, and the runner held at third once. Eight of 25 base runners who started on second when a single was hit to Harper in center field last year held at third base. On average across the league, runners held at third on a single to center 20 percent of the time.

Span understands third base coaches are going to doubt his arm more often. His hard charges at singles, he hopes, will cut that down. If not, he’s okay with it. After he throws out a runner at the plate, he said, he likes to look into the stands at the scout section, at the men who doubt his left arm.