You may have seen this play from a couple week ago, when Cincinnati Reds speedster Billy Hamilton somehow evaded a tag in a game against the Pirates:
Last night, Braves outfielder Jason Heyward pulled off a similar move against the Marlins. The thing is, Hamilton's listed at 6'0", 160, and widely acknowledged to be the fastest player in baseball. Heyward's a fabulous athlete, but he's also 6'5", 245, so there's a lot more of him to contort along the baseline.
(Note that the Marlins third baseman is Casey McGehee. Note, too, that when I discussed what a nice year he's having, I didn't talk about defense.)