Duke to start for Detwiler on Monday (Harper out with bruised knee)

With Ross Detwiler's back a concern, the Nationals will turn to long reliever Zach Duke for Monday's start, according to multiple reports from San Diego. Detwiler was forced to leave Wednesday's start after three innings because of spasms in his lower back suffered when reaching for a throw covering first base. An MRI revealed some "irregularity," so the left-hander will miss at least one start. Detwiler has been one of the Nats' most consistent pitchers, going 2-4 with a 2.76 ERA in eight starts. Duke has struggled with the transition from starter to reliever, pitching to an 8.40 ERA (14 earned runs in 15 innings) in eight appearances out of the bullpen. The left-hander will be making his first start since July 10, 2011 with Arizona. As for today's game, Bryce Harper is again out of the lineup, marking the third time he hasn't started in five games since running face-first into the right field wall at the Los Angeles Dodgers. It is not yet known why Harper isn't in the lineup. Update: Harper is sitting out tonight because of a sore left knee, according to reports. Without the 20-year-old, the Nats have Tyler Moore in right and Steve Lombardozzi in left. Jordan Zimmermann takes the mound looking to extend his personal winning streak to five in a row. The right-hander is in the middle of a remarkable run in which he has pitched at least seven innings in four straight starts and in six of his last seven. For the Nats CF Denard Span LF Steve Lombardozzi 3B Ryan Zimmerman 1B Adam LaRoche SS Ian Desmond RF Tyler Moore 2B Danny Espinosa C Kurt Suzuki RHP Jordan Zimmermann For the Padres SS Everth Cabrera RF Will Venable 3B Chase Headley 1B Yonder Alonso LF Mark Kotsay 2B Jedd Gyorko CF Chris Denorfia C John Baker LHP Eric Stults