The two clubs will face off at Citizens Bank Park for the second of a three-game series. Halladay will pitch for Philadelphia, while Washington counters with Jordan Zimmermann.
Halladay, who is 11-1 with a 2.28 ERA in his career against the Washington franchise, presents an obvious test for the Nationals. However, they have been hitting the ball better as of late. After an April in which they hit .226 and scored 3.4 runs per game, Washington entered Monday's game hitting at a .267 clip with an average of 4.3 runs per game in May.
The Nationals needed just two runs in Monday's 2-1 victory that brought the Phillies' losing streak to three games. Philadelphia, which dropped back under .500, will look to get back to its winning ways on Tuesday against Zimmermann.
After starting the season with a 1-1 record and a 1.38 ERA, Zimmermann is 1-3 with a 3.91 ERA. He's actually pitched better on the road (2-1, 1.35 ERA) than at Nationals Park (0-3, 3.34).
The Phillies tagged Zimmermann for three runs in a 9-3 win on May 6. But in their three consecutive losses leading up to Tuesday, the Phillies are 4-for-31 with runners in scoring position.
Most of the talk surrounding this series has centered on the budding rivalry growing between Washington and Philadelphia.
"I think it will be [a rivalry] if it's not already," said Washington's Brad Lidge, formerly Philadelphia's closer. "In my opinion, the Phillies are always going to maintain a good team. And the Nationals are going to keep going up. If it's a rivalry right now, I don't know. It's one of those deals where this year on this team, we're looking at anybody who is in front of us or could be in front of us. It's a tough division.
"That being said, obviously, myself and [Jayson] Werth and a few guys who have been in Philadelphia, we know how tough the Phillies can be. Needless to say, we keep them in mind when we think about winning the division."
Nationals: Johnson expects Strasburg to make next start
Right-hander Stephen Strasburg is expected to make his next start after leaving Sunday's game against the Orioles after five innings with tightness in his right biceps, manager Davey Johnson said.
"I wasn't really concerned that much after he came out. I thought it was normal tightness," Johnson said before Monday's win. "But anything at all with him, everything with him is magnified. He's going to make his next start, and that's all I know."
Strasburg is 4-1 with a 2.21 ERA and a 64:13 strikeout-to-walk ratio in nine starts this season.
Phillies: Worley seeks second opinion on elbow
Phillies right-hander Vance Worley visited orthopedist James Andrews in Pensacola, Fla., on Monday to receive a second opinion on his elbow, general manager Ruben Amaro Jr. said.
Worley, who is 3-2 with a 3.07 ERA in seven starts, was placed on the 15-day disabled list on Wednesday with elbow inflammation and also has a bone chip. He said Sunday he was hoping to begin throwing again in the next few days.
Kyle Kendrick has taken Worley's spot in the rotation. He was the pitcher of record in Monday's loss to Washington but was hurt by poor run support. He surrendered just two runs on five hits in seven solid innings, retiring the last 11 batters he faced.
Lidge has been cleared to start throwing off a mound. He had surgery for a sports hernia on May 1. The target date for his return is June 15.
"I feel good. It's surprising how good you can feel in three weeks," Lidge said.
Phillies third baseman Placido Polanco started his first game since last Wednesday after sitting out with a sore left ankle. He went 2-for-4 with a walk.
Bryce Harper, after saying he hoped to get booed in Philadelphia (the fans obliged), went 2-for-4 and scored a run in Monday's series opener.
From 2007-10, the Phillies were 51-21 against the Nationals. Since then, they're 9-13.
Monday marked the first of 20 straight games the Phillies will play against teams with records above .500.