O's game blog: It's Chen against Gonzalez tonight at Camden Yards

Orioles left-hander Wei-Yin Chen (8-3, 4.12 ERA) faces a challenge tonight. Not only is Washington sending out a pitcher against him that has thrown 22 straight scoreless innings, but the Nationals are a much better hitting team against lefties. The Nationals are hitting .234 with a .376 slugging percentage against right-handed pitchers but .281 with a .408 slugging percentage against southpaws. That team average ranks second in the majors against lefties and Washington is seventh in OPS. Several Nats hitters have robust numbers versus left-handers: * Jayson Werth bats .375 with a .930 OPS. * Anthony Rendon bats .358 with a .972 OPS. * Bryce Harper bats .394 with a 1.065 OPS. * Ryan Zimmerman bats .270 with a .781 OPS. Now it is worth noting that Chen is better this year against right-handed batters than left. Right-handed hitters bat .270 off him and lefties are batting .327. Since pitching to an ERA of 4.50 in April and May, Chen is 3-1 with a 3.57 ERA in seven starts since June 1. In 10 home starts he is 4-2 with a 3.84 ERA. Chen has been giving up more homers lately. He's allowed seven over his last four starts and 12 in the last eight. Over his first nine 2014 starts, Chen gave up just four home runs. Gio Gonzalez (6-4, 3.52 ERA) has not allowed a run over his last 22 innings heading into tonight's start. He pitched 21 scoreless giving up just nine hits over his past three starts against the Brewers, Cubs and Cubs. In that stretch opponents are batting just .132 against him. Gonzalez has given up an ERA of 8.31 in the first inning this season and 4.15 in the second. From the third inning on his ERA is 2.13. Gonzalez is 1-2 with a 3.75 ERA in six career starts against Baltimore, the first five of which came when he was with Oakland. He started for the Nats against the Orioles on May 27 and gave up four runs and eight hits over 5 2/3 innings.