The Nationals and Diamondbacks were tied at one after four innings, and it looked like they'd finish the fifth that way. But then Scott Olsen walked Miguel Montero with two outs, putting two runners on for Mark Reynolds, who clubbed a homer to center to put Arizona up 4-1. It split open what had been a decent game so far for Olsen.
Washington's main source of offense so far has come from Ryan Zimmerman, who's 2-for-2 with a solo homer. Zimmerman is 4-for-10 with a 1.255 OPS this month. He's on a legitimate tear right now.
Olsen has thrown 75 pitches through five innings. He's probably got another inning in him, but the Nationals will have to rally on Joe Saunders.