A 12:10 p.m. PT start on Wednesday meant that right-hander Dan Haren wouldn't get a full rest between outings, so Dodgers manager Don Mattingly tabbed 24-year-old rookie Carlos Frias for the series finale against the Nationals.
It seemed like the obvious choice.
"We felt like he was a good guy for this 12 o'clock start," Mattingly said. "He's young. He doesn't need sleep."
Frias will get the start against Nationals right-hander Jordan Zimmermann in a matchup between the two teams with the best records in the National League. The Dodgers are looking to extend a two-game lead over the second-place Giants in the NL West, while the Nationals try to pad a seven-game lead over the Braves in the NL East.
Frias has pitched solely out of the Dodgers' bullpen at the Major League level, posting a 5.65 ERA in 14 1/3 innings. But Frias has been a starter in the Minors throughout his seven years in the Dodgers' system. He went 10-5 with a 4.58 ERA in 21 games (20 starts) between Double-A and Triple-A this season.
And he's shown just enough in long relief to entice the Dodgers to start him over veteran Kevin Correia. Frias' primary weapon is a sinker that he can throw in the mid-90s. Mattingly has told Frias in the past to not overthrow it -- to rely on movement instead of sheer velocity, and the manager has been pleased with Frias' progress.
"We feel like he's been throwing the ball good," Mattingly said. "We can't say he matches up because he hasn't seen these guys, but we felt like his stuff is power stuff. Kevin is not really a great matchup if you look at the numbers."
Just eight games into his Major League career, Frias is looking forward to his first opportunity to start a game.
"I'm excited," he said Tuesday. "I couldn't watch the game Monday, I was at the hotel. But I'll watch the hitters tonight, get an idea of what they like to hit. I like to do that the game before I start. I knew Sunday when I threw my bullpen session and I was preparing in my mind for Wednesday."
For the Nationals, Zimmermann is looking for his third win in as many starts.
The right-hander, who is 10-5 with a 2.93 ERA on the season, scattered seven hits in a six-inning, two-run effort in Seattle his last time out. Zimmermann said he struggled to keep his fastball down early in the game.
"It was one of those games I had to battle the whole game," Zimmermann said. "Nothing came easy. I was in a few jams, but I made the pitches to get out of them."
Zimmermann is 2-1 with a 5.61 ERA against the Dodgers in five career starts.
Nationals: LaRoche sits, gets treatment for back
First baseman Adam LaRoche was given the day off Tuesday because of lower back tightness. Manager Matt Williams didn't rule out LaRoche having the day off Wednesday afternoon. Including the off-day on Thursday, LaRoche could have three days off.
"We are going to give him today and evaluate tomorrow morning and see how he is," Williams said.
LaRoche has been dealing with back problems for the entire road trip, but the pain grew worse in his final at-bat in the fifth inning against the Dodgers on Monday. LaRoche said he took muscle relaxers and the back feels "a little better." He was expected to spend most of Tuesday getting treatment.
"I don't know if that's temporary. … I would assume today is more treatment than actually going in and pushing it," LaRoche said.
Dodgers: Mattingly benches struggling Puig
It's a sink-or-swim situation for Yasiel Puig, and manager Don Mattingly said Tuesday that it's time to get Puig swimming again.
Mattingly benched the slumping Puig on Tuesday, giving Joc Pederson, the team's No. 3 prospect, his first Major League start against Doug Fister and the Nationals. Pederson batted seventh and played in center field. He collected his first career hit in the second with a bloop single to center off Fister.
Mattingly said he hopes the time off gives Puig a chance to fine-tune. He wouldn't say whether Puig would return to the lineup Wednesday.
"It gives you a chance to work," Mattingly said. "There's a saying, 'You can't see the forest from the trees.' Sometimes you get so close to it and you're trying and trying and you're almost fighting yourself."
• Nationals center fielder Denard Span received a scheduled day off against the Dodgers on Tuesday. Span and Williams planned the off-day as recently as Monday.
• Along with Frias, the Dodgers called up infielders Miguel Rojas and Erisbel Arruebarrena on Tuesday. Their roster stands at 33 players.
Michael Lananna is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.