Having Gio Gonzalez on the mound and a healthy Jayson Werth in the lineup could help them do it again as the NL East-leading Nationals open this four-game set with the Miami Marlins with a doubleheader Friday.LaRoche is batting .325 with five homers in 20 games since the All-Star break, a stretch that started when he had three hits and two runs in a 5-1 victory at Miami on July 13. That win was also Washington's first against Johnson (6-7, 4.04 ERA), who had been 8-0 with a 3.31 ERA in his previous 15 starts against the division rival.The Nationals (62-42) are expected to face Johnson in the second game of this doubleheader, and LaRoche will likely have a say if they're going to beat him again.The first baseman is 7 for 24 against him lifetime, but four of those hits, including a pair of doubles, have come in six at-bats this year.LaRoche is also entering this twinbill with a .432 average, four homers and nine RBIs in his last 10 games. He had a solo homer among his three hits and two RBIs in Thursday's 3-0 win over Philadelphia.Werth hit behind LaRoche on Thursday, going 1 for 3 with an RBI in his return from a broken left wrist injury that sidelined him since May 6. Werth may be 4 for 17 versus Johnson, but LaRoche is happy to have him back as Washington tries to pad its 2 1/2-game lead over second-place Atlanta."It's huge to have him back, having him back in the lineup, back in the outfield, back in here," LaRoche said of Werth.The sluggers may be looking to capitalize on Johnson's struggles on the road. The right-hander is 1/3 with a 5.48 ERA in eight starts outside Miami, but enters this meeting coming off two strong performances at home.He went 1-0 in those outings, allowing two runs -- one earned -- and three hits with 13 strikeouts in 11 innings. Both of those runs, however, came Sunday, when he battled through five innings while tying a career high with six walks in a 5-4, 10-inning win over San Diego."Just a mess, but I found away to clean up, I guess," Johnson said. "I don't know how, but I made pitches when I needed to."Gonzalez (13-5, 3.27) is scheduled to face Johnson, and he's among the NL leaders in wins and strikeouts (137). The left-hander, though, is 1-2 with a 4.84 ERA in four starts.Gonzalez's struggles continued Sunday, surrendering five runs and a season high-tying five walks in six innings of an 11-10 win in 11 at Milwaukee.He was charged with a 2-1 defeat in his only season meeting with the Marlins on July 14, allowing two runs and striking out nine in six innings.The Nationals are expected to recall John Lannan (1-0, 2.57) from Triple-A Syracuse to start the first game. His only start this season came in the same scenario July 21. He allowed two runs and five hits and hit two batters in seven innings of a 5-2 win over Atlanta.The left-hander, who went 10-13 in 2011 with Washington, is 6-10 with a 5.24 ERA in 19 starts in the minors. He's 0-4 with a 5.50 ERA in his last six starts against the Marlins, losing all three at home.The Marlins, losers of 11 of 15 after falling 6-1 at Atlanta on Thursday, are scheduled to counter Lannan with a minor leaguer of their own in Brad Hand.Hand is 8-5 with a 3.66 ERA in 22 starts for Triple-A New Orleans, and he's expected to be recalled in order to make his season debut.The left-hander went 1-8 with a 4.20 ERA in 12 starts as a rookie with the Marlins last year. He went 0-1 with a 4.70 ERA in two meetings with the Nationals -- both in Washington.