Nationals Manager Matt Williams, center, was able to test the new instant replay system against the Houston Astros. (Rob Foldy/Getty Images)

Jose Lobaton ripped his helmet off and trotted off the field, mad at himself for wasting his final chance of the day with a double-play grounder. A sudden chain events — a flash of a monitor, a walkie-talkie call, a manager emerging from the dugout — turned Lobaton’s anger to confusion. He had hit into double plays, but his manager had never told him to remain on first afterward.

“I was like, ‘Why?’ ” Lobaton said.

On Wednesday afternoon, the Washington Nationals ventured into the new baseball territory of instant replay challenges. Manager Matt Williams had made Lobaton stay on the field because he wanted to practice the Nationals’ system for challenging calls, a process that will play out amid debate — do you prefer human error or making use of technology — all season.

Williams lost his challenge, and the sixth inning of the Nationals’ 10-9 loss to the Houston Astros ended 45 seconds later than it would have otherwise. But he viewed the decision as a success. Before Wednesday, the Nationals had not played in a spring training game equipped to test the challenge system. The Nationals had prepared all spring, and they sent their entire major league coaching staff to Kissimmee, carrying the unusual hope a close call would go against them.

“It’s like, okay, we finally get to work the system,” Williams said. “So it was good.”

The Nationals had been waiting. Earlier in the week, Williams held a 45-minute team meeting about the replay system.

The new system had stirred debate within the clubhouse. Some players believe more correct calls are worth the tradeoff of a few extra minutes. The system may even showcase umpires’ proficiency. Entering Wednesday, managers in the Cactus League and Grapefruit League had challenged 21 calls. Only one had been overturned.

“Everybody wants the calls right,” Nationals outfielder Nate McLouth said. “It’s very important. But you’ll see how many calls the umpires do get right. With the enhanced replay, you’ll see how good these guys are.”

Others remain unconvinced. They have played without replay their whole lives. They resist change as much as delays.

“I’m skeptical about it,” Nationals right-hander Tanner Roark said. “It’s going to slow down the momentum greatly — of a pitcher, of the ballclub.”

This spring, first baseman Adam LaRoche has sidled up to umpires to ask questions about the challenge system. His knowledge hasn’t convinced him the change will be worthwhile.

“I’m not a big fan,” LaRoche said. “I always wonder where it’s going to stop. It’s not necessarily what they’re doing now but what this might lead to.”

Some players worry the replay system could alter the complexion of games. Managers receive one challenge to start the game. If they use it and they’re wrong, they cannot challenge again. (But they can attempt to convince an umpire to review a play on his own.) If they use it and they’re right, they can challenge again but only in the first six innings. If a manager’s challenge remains unused late in the game, he can still use it, perhaps with ulterior motives.

“The managers can play some strategy with it, stalling the game,” pitcher Craig Stammen said. “. . . I don’t like that.”

As Wednesday’s split-squad game wore on, Williams worried it would pass without a chance to challenge. In the first inning, Jason Castro ripped a double to right field, and McLouth’s throw nearly beat him to second.

Bench coach Randy Knorr used his walkie-talkie to ask video coordinators Erick Dalton and Chris Rosenbaum if they should use a challenge. After watching the replay in a booth above the field, Dalton radioed back, “He beat it.”

(During the season, the Nationals will have a land-line phone, and Dalton and Rosenbaum will be stationed in a room behind the clubhouse, watching a live feed.)

In the sixth, the Nationals’ chance arrived. With Jamey Carroll on first after a single, Lobaton chopped a groundball up the middle. Astros shortstop Jonathan Villar flipped to second baseman Gregorio Petit, who fired to first baseman Japhet Amador. Lobaton and Altuve’s throw arrived at about the same time. First base umpire Ryan Blakney pumped his fist, signifying an inning-ending double play.

In the dugout, Knorr’s walkie-talkie crackled. Williams turned to look at Knorr. Dalton told Knorr, “Challenge it.” Knorr relayed the message to Williams, who trudged out of the dugout. Williams specified to Blakney he wanted the call at first base — not second — reviewed. Umpires spent 45 seconds wearing headphones, receiving word from a replay official that their original call was correct.

The Nationals experienced the other end one inning later. Astros Manager Bo Porter’s challenge turned the third out of the seventh inning into an infield single. The next hitter produced an RBI single.

Before Porter’s challenge, Nationals fielders began jogging into the dugout. Coaches rushed to the top of the dugout and urged them to remain on the field. Williams and his staff have instructed them play through close third out calls as if the inning contains four outs. In some circumstances, a runner’s choice after the apparent third out could decide a game.

Imagine: tie game, ninth inning, runner on second, two outs. The shortstop makes a play in the hole and fires to first. The batter is called out on a close play, and the runner on second continues home. With replay, fielders must try for the fourth out at home to convince the umpires the run should not count in the event the play at first is reversed.

“You got to be prepared. You got to have awareness,” Knorr said. “We’re telling them, you have to be absolutely, 100 percent sure that you got him out. If there’s any doubt in your mind, you’ve got to look for another play. It’s something that we got to get used to.”