MLB Advanced Media, the tech outfit owned by baseball’s 30 clubs, is rolling out a new tracking technology that yields insights about the entire field of play — not just the pitch or the hit. Through a combination of cameras, radar, and proprietary software, the new system provides data on a base runner’s jump and speed and the angle of his path while trying to, say, steal second base. It can also capture information on the catcher, fielders, and more.

Using this still-unnamed technology, MLBAM (known internally as BAM) crunched some numbers exclusively for Fortune that suggest that the single fastest guy in baseball is probably Cincinnati Reds rookie Billy Hamilton: In a September game against the Milwaukee Brewers, Hamilton, who was called up from the minors last season just for the playoffs, successfully stole second base in the eighth inning. The new system revealed that he had a 10.83-foot lead, clocked a jump of 0.49 seconds, and hit a top speed of 21.51 mph (rather insane), and that the entire steal occurred in only 3.08 seconds. Meanwhile, it took the Brewers’ catcher 0.667 seconds to get the ball out of his glove and release his throw to second; his throw traveled at 78.81 mph — fast, but not fast enough to tag Hamilton out.

Bob Bowman, CEO of MLBAM, says it is the fans who are driving the league’s aggressive push into capturing ever more granular bits of information about its players.

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Such data can help turn casual viewers into “seamheads” — baseball slang for sabermetrics fanatics — or simply get fans more invested in their favorite player’s performance, prompting them to buy a jersey or spring for tickets to a game.

Also at stake: Big Data bragging rights. Professional baseball has long been a leader in the increasingly crowded sports-analytics field — its use of the Pitchf/x tracking service dates back to 2006, long before most other professional leagues were embracing such technology. “They have at least five years on everybody else,” says Dan Neely, CEO of Networked Insights, an analytics company that has worked with sports clients.

Of course, all this data could be a big boon to teams too. Such detailed individual stats can transform the way teams train, strategize, and, yes, trade and value players. The new system is in only three stadiums this season: those of the Twins, the Brewers, and the Mets. The league plans to roll it out to all 30 parks by 2015. Right now it takes almost an hour to deliver replay footage overlaid with the newly collected data, in part because statisticians need to crunch the numbers for each play. But eventually, Bowman says, the league aims to be able to churn out data-rich replays almost immediately. Or at least as quickly as Billy Hamilton steals a base.

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This story is from the April 28, 2014 issue of Fortune.