Tony Tribble / AP

The Nationals called up first baseman Chris Marrero not only as their 26th man for today’s doubleheader, but also as a possible ingredient to halting their season-long offensive slump.

General Manager Mike Rizzo declined to say whether Marrero would remain with the Nationals after today, and Marrero said he had not been informed of his status beyond today’s doubleheader. But one person familiar with the situation said the Nationals plan to keep Marrero on their active roster for more than just one day.

“The rules allow us to keep the 26th man up,” Rizzo said. “We thought it was the right thing to do. We’ve got an extra bullpen arm already. We felt this was the most prudent way to utilize the roster.”

With Marrero on the roster, nine of the Nationals’ 26 active players began the year in the minor leagues.

It may feel like Marrero, the Nationals’ top draft pick in 2006, has been in the Nationals’ organization roughly forever. Despite a professional career that began when Bryce Harper was 13, Marrero is making his second trip to the majors at just 24 years old.

“There’s always ups and downs,” Marrero said. “You just got to overcome them.”

Marrero’s first hurdle came in 2008, when he broke his ankle sliding into home plate at Class A Potomac. He recovered and made his major league debut in a September call-up in 2011. The Nationals slated him to be part of their bench in 2012, but in winter ball leading up to the year he tore his hamstring. The injury sidelined him in spring training, and he struggled at Class AAA Syracuse as he tried to play through it before the injury had fully healed.

“His development was on schedule, expect what you can never account for,” Rizzo said. “The injuries have set him back greatly. We’ve always liked him as a good offensive player for us and a guy that could help us on the major league level.”

This spring, Marrero surprised Nationals officials with his power, blasting balls with more authority than he had even before his hamstring injury. In 55 games at Syracuse this year, Marrero has hit .305/.355/.502 with 10 homers. His career high for home runs in a full season is 23, back in 2007, when he split time between Potomac and Hagerstown.

“I’m just happy,” Marrero said. “The hamstring was a big injury. I worked hard to get it back in shape, and this is where I wanted to be.”

With Tyler Moore having struggled for the first two months of the season, Marrero could give the Nationals a lift in an area they badly need one. The Nationals have hit .198/.265/.303 this season against left-handed pitchers, the worst average, on-base percentage and slugging percentage in the majors against lefties.

If the Nationals do indeed keep Marrero on the roster, they would have options. They could simply send down spare bullpen arm Xavier Cedeno, giving them a standard seven-man bullpen and five-man bench. But Marrero and Moore would be redundant pieces, and so the Nationals could option Moore, who has hit .149/.198/.266 in 101 plate appearances.