The sensational Harvey (7-1, 2.05 ERA) will be the main attraction as he pitches in front of his home fans for the first time since his lone defeat June 13 against St. Louis. He has bounced back with consecutive victories, allowing two hits in six innings Sunday in an 8-0 win at Philadelphia in a 72-pitch outing cut short by rain.
Harvey leads the NL with 121 strikeouts and his 191 through 26 starts are the sixth-most since 1916 by any pitcher in that span to start a career. He also leads the majors in opponent batting average (.188) and WHIP (0.88).
The right-hander is 1-1 with a 1.50 ERA in two career starts against the Nationals, yielding one run over seven innings with seven strikeouts to beat Stephen Strasburg in a 7-1 victory April 19.
New York (32-43) will also have Wright back in the lineup after the third baseman was rested in Thursday's 3-2 victory at Colorado in a makeup game. It's the first game he missed.
"In a perfect world, I like to play at home and against our division rivals," Wright told the Mets' official website. "So that leaves very few choices as to when (to rest)."
Wright is hitting .371 over his last eight games, and he's 6 for 15 against Detwiler (2-6, 4.18).
The Nationals are winners of four straight and five of six in Detwiler's starts against New York. He's 3-1 with a 3.31 ERA in those six outings - none this year.
The left-hander, however, is 0-2 with an 8.59 ERA in three starts since being activated off the disabled list June 13 after being out due to a right back muscle strain. He matched a career high by yielding seven runs over 3 2-3 innings in Sunday's 7-6 defeat to the Rockies.
Manager Davey Johnson believes the 27-year-old is still learning how to be effective.
"Basically he's a sinkerball pitcher," Johnson said. "He's still very young, learning how to use all the weapons in his arsenal.''
New York has outscored Washington 27-12 in winning three of five meetings.
Thursday's victory capped a 7-4 trip for the Mets, who own baseball's worst home mark at 14-23. They are a respectable 15-12 against left-handed starters.
The Nationals (39-39) missed a chance to improve to two games over .500 for the first time since May 28 with Thursday's 3-2, 11-inning defeat to Arizona. Ian Desmond's two-run homer offset one by the Diamondbacks, who used a bunt single in extra innings to prevail.
"It was that kind of ballgame," Johnson said. "A couple home runs, and then a safety squeeze beats us.''
This is expected to be the final series Washington plays without Bryce Harper, slated to return Monday against Milwaukee.