By June of 2013, Baltimore’s beat writers had established their favorite in-season stat to track: Manny Machado’s rapidly rising doubles count.

Machado was in the midst of his first full season in the majors and on pace to make a run for the single-season doubles record. He finished the season with 51 (a several-way tie for 51st all-time), but in the moment, he represented a rookie with sky high potential, standing in the shadow of a mountain representing his own potential peak.
As he dumped double after double into the outfield, Orioles broadcasters noted for fans that the 20-year-old Machado was still developing physically, so his power tool was poised to level up as his career progressed, and when it did, some portion of those 51 two-baggers would convert to round-trippers. The Doubles to Dingers developmental arc is a real phenomenon. After hitting a double once every 14 plate appearances and a home run once every 50 in 2013, Machado followed up that performance in ’14 by doubling just once every 25 PA while upping his homer rate to once every 30. More recently, the current Baltimore broadcast booth has applied the Doubles to Dingers arc to Gunnar Henderson, another promising second-year player on the left side of the Orioles’ infield. However, as Henderson has increased his home run rate in his second full season by over 50%, his doubles rate has held steady, suggesting he’s leveled up his hit tool alongside the power surge, which doesn’t quite fit this narrative arc.
So which players have best exemplified the Double to Dingers storyline, and how did their stories play out afterward? We don’t need to rely on broadcasters, who have a tendency to fuel fan optimism, because this is extremely quantifiable. To identify players on this path, I started the search in 1988 and looked only at players who at the time had three or fewer seasons of at least 100 PA in the majors. I compared their ratio of dingers to doubles during the season in question to their career ratio for all seasons prior. Only samples of at least 300 PA were considered when calculating the ratio. Players also needed to be hitting doubles in at least 4% of their PAs prior to unlocking the next level of power, and after leveling up, their new homer rate should settle in above 2% of PAs (thresholds chosen are round numbers at or just below league average because this really only matters for hitters producing at a baseline level of competency in both key categories). To further ensure that the change in their dingers-to-doubles ratio is caused by a somewhat proportional change to the frequency of both doubles and dingers, their homer rate needed to increase by at least half a percent; likewise, their doubles rate must have decreased by at least half a percent. Read the rest of this entry »