SAN FRANCISCO -- As the Nationals took batting practice at Oracle Park prior to Tuesday night's game against the Giants, their newest infielder Asdrúbal Cabrera, whose signing was made official earlier in the evening, ventured out to first base.

Cabrera has played in more than 1,600 games in the big leagues in his 13-year career, but never at first base. He has exclusively played third base for the Rangers this season. But the Nationals will ask their newest bench player to learn first base, hoping to increase his flexibility for a reserve unit that has been depleted recently.

"This is new for me, but I've played short, third and second base before," Cabrera said. "I'm going to keep doing what I'm doing, prepare myself to do all the best in the field."

The Nationals added Cabrera to improve a bench currently without two of their best hitters. Matt Adams, their top left-handed pinch-hitter, has been called into everyday duty at first base to fill in for Ryan Zimmerman. Howie Kendrick is on the injured list with a left hamstring strain. That leaves the Nationals without a true backup first baseman, even though Gerardo Parra has filled in at the position when necessary.

"I want [Cabrera] to get comfortable over there," manager Dave Martinez said. "I'm not going to just throw him in there, but I think he can do it. He's got really good hands, footwork."

Cabrera should also provide an upgrade as the backup infielder over Adrian Sanchez, who was optioned to Double-A Harrisburg in his place. Cabrera, who played a half season in Washington after being acquired at the Trade Deadline in 2014, hit 12 homers with an 80 OPS+ in 93 games with Texas this year before he was designated for assignment.

"Gives us another bat," Martinez said. "Switch-hitter, power, hits the ball all over. Great addition for us. I'm excited that he's here. I told him just be ready, you can play everywhere, come in, double-switch and help us in many ways."

Nats DFA Barraclough

To create room for Cabrera on the 40-man roster, the Nationals designated reliever Kyle Barraclough for assignment Tuesday, ending his rocky tenure with the team. Barraclough was one of the Nationals' first offseason additions, acquired from the Marlins to help revamp the back end of the bullpen.

But neither Barraclough or Trevor Rosenthal ever worked out for the Nationals. Barraclough appeared in 33 games and pitched to a 6.66 ERA and 1.75 WHIP. He allowed eight home runs, matching his career high in just 25 2/3 innings. In his last appearance with the Nats, he surrendered a go-ahead three-run homer to the Dodgers' Justin Turner, before being optioned back to the Minors.

"It's tough because we do our due diligence over the winter time," Martinez said. "We get these guys, but yet then again, it's a long season and things happen."

When a player's contract is designated for assignment -- often abbreviated "DFA" -- that player is immediately removed from his club's 40-man roster, and 25-man roster if he was on that as well. Within seven days of the transaction (it was previously 10 days), the player must either be traded, released or placed on irrevocable outright waivers.

Worth noting

• Max Scherzer took the day off from throwing Tuesday as he continues to test his injured back. After making about 40 throws at 65 feet the day prior, Scherzer arrived to the ballpark feeling "OK, wasn't great but OK," according to Martinez. The Nats elected to give Scherzer the day off and Martinez said depending on how Scherzer feels in the morning, he may not resume throwing until Friday in New York.

• Scherzer chose the nickname "Brown Eye" for his nickname on his Players' Weekend jersey, a follow-up after going with the name "Blue Eye" one year ago.