Eury Perez (John McDonnell/TWP)

The Nationals officially placed Jayson Werth on the 15-day disabled list on Saturday afternoon with a mild hamstring strain and called up outfielder Eury Perez from Class AAA Syracuse. The team still expects Werth will return in about a week. Perez was informed of the move on Friday afternoon, packed his things and drove down to Washington from upstate New York with a cousin.

At Syracuse, Perez, 22, was off to a torrid start. He is hitting .346 with a .352 on-base percentage and seven stolen bases in eight attempts in 23 games. The other call-up option was Jeff Kobernus, an athletic Rule 5 pick player returned to the Nationals from the Tigers late this spring. But Perez was already on the 40-man roster and Kobernus wasn’t.

“We like them both but one guy is a converted outfielder and I need an outfielder,” Manager Davey Johnson said.

Perez made his major league debut last fall but played little, going 1 for 5 and appearing in 13 games. The Nationals rewarded his renewed focus and rise through the minor league ranks with a September call-up. He is a contact hitter to all fields, a speedy base-runner and outfielder.

“I thought last year at time he felt a little bit out over his skis,” Johnson said. “That’s inexperience. I think he’s going to be more comfortable being here. I think that’s all part of maturity and experience. I love his talent.”

Perez spent most of spring training with the Dominican national team in the World Baseball Classic. Johnson wasn’t pleased Perez received little playing time in the tournament — he appeared in two games and had only one at-bat — but also saw the experience as valuable. The Dominican’s star-studded team won the WBC title and Perez called the experience “one of the best things that could ever have happened.”

Perez said he gleaned tips about the game from being around Dominican all-stars Edwin Encarnacion, Robinson Cano and Miguel Tejada. He said he has felt stronger this so far this season, incorporating more lifting into his offseason routine. “I’m here to help and do the best I can,” he said.

He may, however, be with the Nationals for only a week.

Werth and General Manager Mike Rizzo both said on Friday that they expect the outfielder to be ready to be ready to return on May 18, the soonest he would be eligible to come off the disabled list. But Werth cautioned that this is the first time he has ever dealt with a hamstring issue in his career and was in uncharted territory. As the Nationals also believe, he felt the dehydration from a stomach bug was a factor in the continued cramping.

“It’s a mysterious thing going on,” Johnson said. “I don’t know. Our trainer doesn’t know. Our doctor, I’m not sure they know either.” Then Johnson, as he normally does, devolved into humor. “He’s got a strange diet,” he continued. “He’s not a vegan. He’s gluten-free. I don’t know what that it. … Maybe he needs a little wheat. I might need to slip him some wheat. He’s either going to keel over and die or get well.”