TV: FOX SportsFlorida

TIME: Coverage begins at 6:30 p.m. ET


WASHINGTON -- The first-place Washington Nationals have five players on the 25-man roster who were not part of the organization when spring training began: outfielder Howie Kendrick and pitchers Edwin Jackson, Sean Doolittle, Ryan Madson and Brandon Kintzler.

The latter three are transforming the bullpen for the Nationals, who host the Miami Marlins on Tuesday in the second of four games in a showdown of National League East teams.

Washington right-hander A.J. Cole (1-1, 4.91 ERA) will start against Miami right-hander Vance Worley (1-2, 5.31).

Cole is 0-1 with a 6.75 ERA in his career against the Marlins. Worley is 5-2 with a 2.78 ERA in 11 games, with five starts, in his career against Washington. Worley is 1-0 with a 1.00 ERA in two games, with one start, this year against the Nationals.

If Cole, who has pitched 11 innings in two starts, can't go deep in the game, he should be able to rely on the Washington bullpen, which was improved greatly in the past few weeks.

Before the non-waiver trade deadline, the Nationals acquired relievers Doolittle and Madson from the Oakland A's and Kintzler from the Minnesota Twins.

"It is like being the new kid in school maybe," Doolittle said Monday, standing in front of his locker in the Washington clubhouse. "I come over and everything is different, everything is new. You have to learn new faces and new teams. …

Kintzler pitched a scoreless eighth inning for the win Monday, and Doolittle tossed a scoreless ninth as the Nationals beat the Marlins 3-2. Doolittle fanned former Washington infielder Tyler Moore for the last out with a runner on base.

All three new Washington relievers have experience as closers.

"It helps a lot when you have three guys who have been in that situation," Washington manager Dusty Baker said after the win. "Everybody is different, and everybody can't really handle that situation for whatever reason. Those three guys in particular have been in that situation many times."

Doolittle was teammates for one year at the University of Virginia with Nationals first baseman Ryan Zimmerman.

"Obviously coming over here, the team was having a good season, the team was in first place," Doolittle said. "You want to lay low and keep your head down, especially in the beginning and kind of observe how they are doing things around here and then see how you fit in."

"It is definitely an adjustment, but I am finding my niche here. I think the biggest thing that has helped is the catchers. They know the hitters better than I do. I know they have done their homework."

Marlins manager Don Mattingly likes how his team has competed this season against Washington, compiling a 5-5 record against the runaway NL West leaders.

"We match up OK. Obviously, they have a very good team," Mattingly said.

But the Marlins, already without injured first baseman Justin Bour, got more bad news Monday as starting pitcher Chris O'Grady left the game in the second inning with a right oblique strain. O'Grady and Bour were teammates at nearby George Mason University.

"I went out for that second inning and just started feeling cramping in my right side," said O'Grady, who was making the sixth start of his career. "I threw a few more, and after the curveball to (Daniel) Murphy, it just kind of tightened up a little bit. Right now it's just day-to-day. I don't know what's going on yet."

Mattingly continues to be impressed with catcher J.T. Realmuto, who was 0-for-4 on Monday but is still hitting .302.

"He's a tough kid. I don't think anything bothers him," Mattingly said of Realmuto, who has 13 homers this year and is second in the National League in road batting average (.359), trailing only Murphy (.368).