Have the Orioles turned the corner against Jon Lester?

If you go by the results starting last season, the days of Jon Lester taking the mound and Boston expecting to beat the Orioles may be over. Since the start of 2012, Lester has started four times against the Orioles, and the O's are 4-0 in those games. Lester has an ERA of 5.25 in the four games, pitching 24 innings and allowing 30 hits with seven walks and 18 strikeouts. He was 14-0 over his first 18 career starts against the Orioles, but is 0-2 over the last four. The O's have a .309 batting average against the lefty in those outings. In three starts last season, Lester went 0-1 with an ERA of 4.26 against Baltimore, and he is 0-1 with an ERA of 9.00 in his one start this year. The Orioles won 6-3 here against him June 16. Over five innings, he allowed nine hits and five runs. Lester is 9-6 with a 4.50 ERA in 21 starts. He was 6-0 with a 2.72 ERA in his first nine starts of 2013, but, over his last nine starts, he is 3-4 with a 5.94 ERA. Facing him today is Jason Hammel, who is 7-7 with a 5.20 ERA over 20 starts. Hammel is winless over his last nine starts, and has allowed four runs or more in four of his last seven outings. Perhaps just as troubling as his inability to maintain consistent command and sink on his fastball this year is that opponents are hitting him much better lately. Over his first 16 starts, opponent hitters were batting .273 vs. Hammel. But, over his last four starts, where he has allowed 35 hits in 24 innings, that average against is .347. While Lester is 5-6 with a 5.61 ERA in 13 road starts, Hammel is 1-4 with a 6.65 ERA in eight home starts. Will something give today? Will one of these struggling pitchers provide a big start for their team in an important series finale?