John Shelby is in charge of the new replay system.

MILWAUKEE -- Brewers coach John Shelby wipes perspiration from his brow, but not because he's sweating his new role as the team's point man on instant replay.

The small office Shelby finds himself confined to during home games is hot. Very hot.

"Oh well," the 56-year-old former Major League outfielder said with a shrug.

Shelby has been shrugging off trials ever since Brewers manager Ron Roenicke first suggested a couple of weeks into Spring Training that he be assigned to monitor video during games and call to the dugout when a replay challenge is in order. Shelby also serves as an outfield instructor and extra coach.

When the game begins, Shelby reports to a small office down the hall from the dugout, just off the larger video room used by players to prepare for games and review at-bats during games. Shelby's setup is much more modest: a desk, a chair, a telephone wired to the dugout and three television screens. One carries the FS Wisconsin broadcast with sound, so Shelby does not have to watch in silence. Another carries a clean, live feed, and the third has a grid of every camera angle at Miller Park.

Once the game begins, Shelby can control how many angles he sees. When a questionable call occurs, he quickly scans for the best view and controls the replay. The system is connected to MLB's state-of-the-art Replay Operations Center at MLB.com headquarters in New York, where a group of umpires are watching the same thing.

"What we see, they see," Shelby said.

MLB instituted expanded replay on Opening Day, and for the first time is allowing umpires to take a second look at force plays, tag plays, fair/foul calls in the outfield, catches in the outfield, hit by pitches, ground-rule doubles, fan interference and baserunning calls.

Each manager gets one challenge per game, and he keeps his challenge if he successfully gets a call overturned. But unlike head coaches in the National Football League, Brewers manager Ron Roenicke does not have a headset to communicate with his eye in the sky. Instead, while Roenicke runs onto the field to discuss a close call, positioning himself with a view of the bench, Shelby takes a quick look, picks up the phone on his desk and passes one of three calls to bench coach Jerry Narron: "Challenge," "no" or "inconclusive." Narron uses signs to relay the call to Roenicke in the field.

All spring, Roenicke and his coaches debated how to best utilize that lone challenge. Would they use it at the first opportunity, or hold it for a key moment in the game?

"We talked about this a lot," Shelby said, "but that play in the first inning could be more important than anything else in the game. So any time there's an opportunity to challenge, we're going to challenge."

However, there is one caveat to that strategy.

"When I tell Jerry to challenge, I'm going to make sure we win that challenge," Shelby said.

That explains why the Brewers did not challenge a close call on Opening Day. Aramis Ramirez was at second base when Lyle Overbay hit a line drive to first baseman Freddie Freeman, who threw to second and doubled off Ramirez. The replay was inconclusive, as Shelby saw it.

Later in that same game, Braves manager Fredi Gonzalez became the first manager to win a challenge under the new system, turning a Ryan Braun infield single into a groundout. In all, replay was used five times on Monday -- four after manager challenges and one implemented by the umpires themselves -- and two calls were overturned. According to the Associated Press, only one call took longer than two minutes to review. The Braun play was the quickest, at 58 seconds.

"The more it's used, the more simple it all becomes," Brewers assistant GM Gord Ash said. "The fear at the beginning was just the unknown of it all."

Last call

Jean Segura's absence from the Brewers' starting lineup Wednesday was no cause for concern, Roenicke said. He plans to give Segura extra rest in the season's early going to ensure the second-year shortstop doesn't have a setback in his throwing shoulder. Segura was bothered by soreness in the final two weeks of Spring Training.

"This was the plan with Segura to make sure we take care of the arm," Roenicke said. "There's been no setbacks, which is great, and I don't want there to be."

• Segura is still searching for comfort at the plate, Roenicke said, evidenced by an 0-for-7 start to the season. Left fielder Khris Davis, also 0-for-7, was out of the lineup as well on Wednesday in favor of Logan Schafer.

"[Segura] is like a couple of other guys in our lineup who are pressing early to get it going right away, which everybody does," Roenicke said. "We need to get him a few hits to get him feeling relaxed."