John Buck continues to make a case why he is the Mets’ MVP so far this season. “With the starts we’ve had from some of our guys so far, I don’t know where we’d be without him,” manager Terry Collins said after yesterday’s 2-0 victory over the Nationals at Citi Field. “The first week of the season, he literally carried us by himself.” Buck got off to a searing start, hitting six homers in his first nine starts before cooling off. He entered yesterday in a 4-for-21 (.190) slide with no homers and just two RBIs in that span. But that changed in a big way in the second inning yesterday, when he crushed a 93-mphfastball from Jordan Zimmermann an estimated 460 feet into the second deck in left-center. “It felt pretty good,” Buck said of his first homer since April 12. “[Zimmermann] throwing it hard gave it a little extra juice.” In the top of the sixth, Mets starter Dillon Gee was cruising, having allowed only three baserunners through five innings. But then he walked Denard Span. With Bryce Harper at the plate, Gee bounced a pitch in the dirt and Span took off for second. Buck scooped up what would have been a wild pitch and easily gunned down Span. That play loomed large when Gee walked Harper and Adam LaRoche before he was pulled in favor of LaTroy Hawkins, who escaped the jam by getting Ian Desmond on called third strike. “That would have been a big run for them,” Buck said. “With Span being a base-stealer, to get him off the basepaths and to get that out when Gee was struggling, that felt good.” Yesterday served as a perfect microcosm for Buck’s season so far.