But the ball hooked foul. It landed harmlessly in the right-field corner, and Nationals closer Rafael Soriano made sure Pederson wouldn't get a chance to hit one straighter. The right-hander spotted a 3-2 slider on the outside corner. Called strike three.
Pederson, the club's No. 3 prospect, had his first Major League at-bat end a 6-4 Dodgers loss.
"We get down to the point where you have to try to win the game," manager Don Mattingly said. "And Joc's the guy for that right there. He's a left-handed hitter, he's a guy who can hit a ball in the gap, score a run.
"It would've been nice of him to hit a double. That ball he hits foul, I would've loved to see it go in the corner. I'd love to see him hit a home run to win the game or at least get on to extend the inning."
But it didn't happen. Pederson, who was called up before Monday's game with rosters expanding, said the ball he lined foul was one he shouldn't have missed, one he'd like to have back.
But he said he didn't shy away from the moment. The 2014 Pacific Coast League Most Valuable Player said to be able to make his debut in that kind of pressure situation was "pretty special."
"That's when you want to be up there, when the game's on the line, whether it's in [Triple-A] Albuquerque or here," Pederson said. "You want to be in when the game matters. You want to have the chance to win the game."
"For us, everybody in the dugout was excited," catcher A.J. Ellis said. "For him, it's a great situation for him to experience that. He put a great swing on the ball, it just hooked foul little bit. He looked calm. He looked comfortable.
"I think he'll look back and he'll probably never remember his first at-bat with the success he's going to have."
The Dodgers also made use of three of their other new faces Monday:
• The club's No. 15 prospect, Yimi Garcia, a 24-year-old right-handed reliever, made his big league debut in the loss, tossing two innings of scoreless relief.
• Infielder/outfielder Alex Guerrero was back with the Dodgers for the first time since the team's opening series in Australia, and he made a pinch-hit appearance Monday night that resulted in a strikeout.
• Right-hander Chris Perez (right ankle bone spurs) came off the disabled list and made his first appearance since Aug. 3 when he came on in relief of Roberto Hernandez in the fifth inning Monday night.
Pederson, a 22-year-old center fielder, was the PCL's rookie of the year and became the fourth player in 112 years of the league's existence to post a 30-home run/30-steal season -- the first since 1934. Overall, he batted .303 with 30 steals, 33 home runs -- tops in the league -- and 78 RBIs in 121 games with Albuquerque.
To make room for Pederson on the 40-man roster, the Dodgers designated infielder Carlos Triunfel for assignment.
Catcher Tim Federowicz also is back for this third stint with the Dodgers after appearing in 18 games earlier this season, and Mattingly said he expected infielders Miguel Rojas and Erisbel Arruebarrena and right-hander Carlos Frias to join the team as soon as Tuesday.