Tim Beckham was just 18 years old when the Rays plucked him out of the green-gold ranks of central Georgia’s Griffin High School with the first overall pick of the 2008 draft and placed the future of baseball’s youngest franchise on his slight shoulders. He’s spent the past decade trying to get over it. This month — after parts of 10 sorry seasons with the Rays summed to a disappointing .247/.299/.421 line over just 791 big-league plate appearances — he might finally have done it. Beckham, still as quick and graceful on the field as he was at 18 but now a soft-spoken and wary 27 off it, has for the past four weeks been an Oriole, and one of the very best hitters in baseball. “He’s definitely been a sparkplug for us, man,” teammate Chris Davis said early Saturday afternoon in Fenway Park’s cramped visitor’s clubhouse, as Beckham sat still and square on a folding chair some 10 feet behind him, brown eyes fixed intently on a television playing highlights from the previous night’s 16-3 drubbing of the Red Sox, in which Beckham and Davis each scored twice and drove in two runs. “It really takes a lot of commitment — a lot of trust — to continue to work towards one goal when you’re not having success,” Davis said. “And I think what you’re starting to see this year is that he’s really starting to put it all together. We always knew that the talent was there. Now he’s showing it.”