The Nationals will play their first Sunday night game since the night Nationals Park opened in 2008, because ESPN producers decided this winter that the Nationals would be a good draw. So far, they turned out to be right – they are in first place at 18-9 and have one of the most electric starting rotations in recent memory.

“You kind of say to yourself, all right, what will compel people to watch this game? What can you give people in a 10-second promo?” Mike Ryan, ESPN’s vice president of programming, said before the season. “That usually comes down to stars. The guys on the Nationals — Strasburg, Harper, the two Zimmerman[n]s — there’s no shortage of marketable players.”

The Nationals will be trying for a sweep of the Phillies after their 7-1 shellacking of them yesterday. They have already grabbed attention, but to sweep the reigning division champs on national television would reinforce the message.

“I don’t think it’s a big secret,” Manager Davey Johnson said. “It’s not a big secret among baseball that we’ve got a good ballclub and we’ve got a lot of good players. It is going to be fun for everybody around to see a team from Washington that’s atop the division playing the division champions. I would have an interest in that, even if I wasn’t in baseball. So it should be exciting. I won’t have to give any motivational speeches tomorrow night, just like I didn’t first game coming in here.”

Jordan Zimmermann will face Cole Hamels, an excellent matchup of 20-something starters. Johnson feels that Hamels’s changeup — “a dead fish low and away to a right hander,” he said — makes him just as effective against righties as lefties.

The Nationals started three lefties Saturday, and “we’ll probably go with that same lineup,” Johnson said. “What the heck?”