In baseball, a ground-rule double is usually called when a batted ball bounces in fair territory on the field of play and then goes into the stands, in which case the batter and any runners are awarded two bases. These can also be called when a ball in play hits or gets lodged in an on-field obstruction; an example of this would be a ball that rolls under the canvas that covers the tarp cylinder at Fenway Park in the right field corner, known as “Canvas Alley.” Some time ago, a story began to circulate, thanks in part to Boston-area television sports reporters, that Fenway was the only ball park in Major League Baseball that included in its ground rules a ruling for a ground-rule triple. Apparently, there was a belief that if a batted ball strikes the ladder on the Green Monster during play, the batter would be awarded three bases. This has also been given credibility by several respected online sources to further perpetuate this belief.
For several years before the Monster Seats appeared above the infamous green left field wall, the Red Sox erected a 23-foot-high net above it in 1936 that stretched its entire length to offer some protection to businesses on Lansdowne Street from home run balls hit over the 37-foot-high structure. To enable groundskeepers to climb up to the netting and retrieve any balls that landed there, a ladder was installed that starts near the upper-left corner of the manual scoreboard, 13 feet above the ground. Once the Monster Seats were installed in 2003, the ladder was no longer a necessity but the team left it in place as a visible reminder of a “forgotten” feature of the ball park.
In truth, hitting the ladder with a batted ball only matters if the ball strikes the top of it and then goes out of the park, in which case the batter along with any base runners are awarded two bases; otherwise, the ball stays in play and batters and base runners alike can advance on their own free will. According to Fenway Park ground rules listed at the official online site for the Red Sox, there is no mention of a ground-rule triple, thereby making it merely an urban myth.