Updated at 6:21 p.m.
The Nationals have promoted Wilmer Difo from Class AA Harrisburg and will have their top infield prospect in uniform Tuesday night against the Yankees in a surprising move necessitated by outfielder Jayson Werth going on the 15-day disabled list with a left wrist contusion.
Difo was summoned to D.C. on Monday night, but the Nationals didn't make the transaction official until Tuesday afternoon, when they determined Werth's injured wrist hadn't healed enough to allow him to return to the lineup.
An MRI taken of Werth's wrist Monday showed no fractures or tendon damage, according to a source familiar with the results, suggesting the injury is not serious. The veteran outfielder, though, needs more time to let the wrist (which was struck by a pitch in San Diego on Friday) heal before he can play, so a stint on the 15-day DL became necessary. The move is back-dated to May 16, so Werth will be eligible to return on May 31.
"It's still swollen," manager Matt Williams said. "So we have to get that taken care of before he can even start back. Three days down already. Not really ready for a few more to even get back to swinging, and then working through that. So it's important for us to have a full 25[-man] roster, and if he's going to be down for another week before he can get back in the game anyway, than we're looking at 10 days."
Difo's ascension to the big leagues is way ahead of schedule — he spent all of 2014 at low-Class A Hagerstown and has played only 33 games this season between high-Class A Potomac and Harrisburg — but his call-up likely will be short-term and isn't indication the organization believes he's ready to play at the major-league level on a regular basis yet.
The Nationals had only four healthy minor-league position players on their 40-man roster: Difo, outfielders Matt den Dekker and Brian Goodwin, catcher Dan Butler. With Michael Taylor, Tyler Moore and Clint Robinson all already on the major-league roster and able to play left field in Werth's absence, the organization didn't necessarily need to add another outfielder to the mix.
"He gives us a lot of options," Williams said. "He gives us another middle infielder without having to move Yunel [Escobar from third base], potentially. It allows us to utilize Dan Uggla a little bit more than ordinary, because he would be the other middle infielder. There's a lot of things that go into it, but he provides a lot of things for us."
Difo, 23, offers the club extra infield help and speed off the bench on a short-term basis. He's hitting a combined .315 with a .367 0n-base percentage and .887 OPS while stealing seven bases in eight tries so far this season. The Dominican native will become the first player signed by the Nationals out of Latin America to reach the big leagues since the 2009 revelation that a prospect claiming to be named Esmailyn Gonzalez had falsified his identity, leading to then-GM Jim Bowden's resignation and the promotion of Mike Rizzo to take over baseball operations.
Difo made an impression on the organization this spring, his first in big-league camp, but he admittedly didn't think his debut would come yet.
"Obviously he was surprised it was so soon, but he felt he was prepared," said bullpen catcher Octavio Martinez, interpreting for Difo. "That's what he works for, to help out any way he can."