In an attempt to improve Jon Lester's terribly underwhelming season, Red Sox pitching coach Bob McClure has pinpointed a subtle mechanical adjustment that the ace lefty will implement today against the Toronto Blue Jays. More likely, though, the biggest thing Lester must change is his luck. "Without making excuses, and he won't make them either, he's going through one of those stretches where every ball is falling in, every ball is getting through," McClure said before last night's 7-3 loss to the Blue Jays at Fenway Park. "I've been through it. I know exactly how he feels. But there's no doubt in my mind, it's going to turn." McClure speaks from experience. In 1983, while pitching for the Milwaukee Brewers, he endured a 10-start stretch in which he went only 1-7 despite posting a 3.93 ERA. Over his next nine starts, he went 7-0 even though his ERA spiked to 4.79. Point is, sometimes it really is all about luck. Lester is 5-7 with a 4.80 ERA, hardly the numbers the Red Sox expect from a top-of-the-rotation starter. But many of his peripheral statistics have remained strong. For instance, he has walked only 2.6 batters per nine innings, the best mark of his career, and his 2.97 strikeout-to-walk ratio is higher than any season since 2009. The problem, it seems, is that Lester is striking out fewer batters (7.6 per nine innings) than his career average (8.3), and the additional pitches that are being put in play are falling for hits. Opponents are batting .331 on balls in play, an improvement from .291 last season and .287 in 2010.