With Matt Wieters out, Pedro Severino will hold down the fort for the Nationals. (Douglas DeFelice/USA TODAY Sports)

ATLANTA — Pedro Severino will join the Washington Nationals in Atlanta Monday, according to people familiar with the situation. They need him because starting catcher Matt Wieters is dealing with an undisclosed ailment that could push him to the disabled list, though the Nationals have not made that decision yet.

Miguel Montero has been an everyday catcher before, though the last time he played more than 100 games in a season was 2015, and he did not come here expecting to fill that role. Severino has never played regularly in the majors for any substantial amount of time, though he has played more than 150 big league innings over the last three seasons. He also started in the 2016 National League Division Series after Wilson Ramos tore his anterior cruciate ligament in late September.

Severino, 25, was on his way to Atlanta Sunday morning before the Nationals took the field at Great American Ball Park, which suggests they played with a three-man bench. Severino appeared in 17 games for the Nationals last season. He went 5 for 29 (.172) with two walks and a double in 31 plate appearances.

Wieters showed no overt signs of trouble in the first two games of the season. He went 1 for 7 with two walks and a run scored. He seemed to direct Max Scherzer and Stephen Strasburg through their starts without incident. Nothing was obvious Sunday morning either, except that he was the only position player not on the field for batting practice before the game. Even injured Daniel Murphy hit with his teammates Sunday.

When Miguel Montero needed someone to catch a few warm-ups while he put on his gear between innings, Wieters took the job. He got in his squat, and looked perfectly normal. But when he threw back to the pitcher, he did so with a truncated delivery that indicated some reluctance to complete a normal follow through.

The severity of Wieters’s injury is not yet clear. The Nationals do not need the 31-year-old to make a substantial offensive impact this year, but Scherzer and Strasburg both prefer throwing to him — so much that he couldn’t get as much rest as the Nationals would have hoped last season as both chased Cy Young Awards down the stretch.

Correction: An earlier version of this story identified Wieters’s ailment as an oblique injury. As of this time, the nature of the injury is undisclosed. The Nationals also did not officially recall Severino; he is merely joining the team in Atlanta in case he is needed.

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