The Nationals, meanwhile, have won seven of their last 10 and have a 2 1/2 game lead over the Mets in the National League East.
Friday: RHP Jeremy Hellickson (4-3, 3.80) vs. RHP Stephen Stasburg (9-0, 2.85)
Saturday: RHP Aaron Nola (5-4, 2.65) vs. RHP Tanner Roark (4-4, 3.21)
Sunday: LHP Adam Morgan (1-5, 6.70) vs. RHP Joe Ross (5-4, 2.92)
Recent history: The Phillies have already faced the Nationals nine times, winning four. All told, the Phillies have won each of their last four games in Washington and five of their last six.
Nationals notes: Strasburg enters Friday night riding a 12-game winning steak, the longest in D.C. baseball history since Walter Johnson won 13 consecutive games in 1924 ... Washington is coming off a three-city, nine-game road trip that matches a season-long 11-day swing. The Nationals were 6-3 on the trip.
Phillies notes: Vincent Velasquez was placed on the 15-day disabled list with a biceps strain. The club recalled RHP Luis Garcia from Lehigh Valley (AAA) to take the open spot on the 25-man roster ... Tommy Joseph has hit safely in 13 of his 15 starts this season, batting .333 (19-57) with 2 2B, 5 HR, 8 RBI, 7 R in those 15 games ... Reliever Hector Neris had a 1.29 ERA through May 30, but he has a 9.82 ERA in his last five appearances.
Up next: The Phillies travel to Toronto for a quick two-game set starting on Monday. The Blue Jays return on Wednesday for a two-game set at Citizens Bank Park to complete the home-and-home series.