Why does David Robertson's fastball appear to have mysterious "hop" to it? Why is Justin Verlander's curveball so hard to hit? And why are even the most accurate radar guns fooling scouts and they don't even know it?

The answers are provided by a Danish technology company that may change the way teams scout and evaluate pitchers. Trackman, a company established in 2003, is taking some old-school observational theory out of baseball and replacing it with hard data derived from 3D Doppler radar ball flight measurement. The company already has established a foothold in professional golf and is bringing its tracking technology to baseball, where Sportvision's Pitch-F/x system, another ball tracking technology, has been used widely for years.

Last year Trackman installed its ball flight measuring systems in a handful of major league and minor league parks. The data provided a trove of information that makes the radar gun, a staple of baseball since the early 1970s, seem as obsolete as the typewriter.

The radar gun, for instance, measures only the speed of a pitch at a given point. But when it comes to fastballs, the battle between the pitcher and hitter is decided by time, not by speed: How long does a fastball take to reach the plate once it leaves the pitcher's hand?

This does not involve one simple math formula because there is a huge variable to consider. While the distance between the pitching rubber and the plate is uniform (60 feet, six inches), the distance the ball actually travels can vary by a foot or more based on where the pitcher releases the ball.

Trackman measures not just the speed of the pitch, but also the key variable: the distance between the pitcher's release point and the plate. With those measurements, Trackman defines not only the time component of a fastball -- "flight time," if you will -- but also defines in irrefutable data why scouts might describe a pitcher as "sneaky fast" or throwing a ball with "hop."

Take, for instance, Robertson, the 5-foot-11 set-up reliever for the Yankees with that "lively" fastball. Robertson does not have exceptional size or velocity, but he ranks fourth among all active pitchers with at least 100 innings in strikeout rate (11.7 per nine innings, better than every pitcher except Carlos Marmol, Jonathan Broxton and Francisco Rodriguez, all of whom are well-paid closers.)

Why is Robertson so difficult to hit? According to Trackman's measurements taken in one American League park last season, Robertson, with his exceptionally long stride and reach, released his fastball seven feet from in front of the pitching rubber -- the largest average extension Trackman measured in that park. The average MLB fastball extension was five feet, 10 inches.

Imagine if Robertson moves the pitching rubber 14 inches closer to home plate every time he pitches. That's the kind of advantage he gains over the average pitcher by releasing his fastball with so much extension. The radar gun (and Trackman) clocks Robertson's fastball at an average of 93 mph. But because Robertson shortens the distance between his release point and home plate, his "effective velocity" is 95 mph. It looks like 93 but gets on a hitter like 95 -- thus the illusion of "hop."

When it comes to "stealing" distance -- and distance equals time for a pitcher - here are the top 10 pitchers from one AL park last year, ranked by fastball extension in feet and inches:

What about breaking balls? Trackman can measure the spin rate of all pitches in revolutions per minute. Pitchers such as Sandy Koufax and Pedro Martinez could throw wicked breaking balls because they had long fingers that could generate tremendous spin, though no could quite quantify it. Spin rate is important for breaking balls because it not only correlates to movement but also to deception.

The seams on a baseball are the decoder ring for a hitter. A fastball spins so fast the hitter does not see the seams, only a solid sphere. But a breaking ball, which does not travel as fast, can offer a clue of its intentions with its spinning seams. The faster a breaking ball spins, the harder it is to see the seams, so the more it looks like a fastball for a greater period of time. "I didn't pick up the spin," is the common lament of a fooled hitter who mistimed a breaking ball.

Acccording to Trackman data from one AL park last year, here are the pitchers with the fastest average curveball spin rate:

Verlander's curveball spins 23 percent faster than an average major league curveball, an astonishing difference. Moreover, you begin to understand the quality of Hunter's stuff when you notice he is the only pitcher to show up among the top 10 for fastball extension and curveball spin rate.

What about sliders? Again, here are Trackman's fastest average spin rates from one AL park last year:

The data is fun and interesting, but it's only valuable because of how it is used, not just how it is compiled. For instance, once you measure fastball extension, just how important is that information? Trackman has that answer, too. It divided all pitchers with at least 100 innings into two categories: pitchers with below the 5-foot-10 average fastball extension and those with above average extension. Then it looked at ERA and strikeout rates. What it found was a correlation between greater extension and a lower ERA and higher strikeout rate:

Trackman also took the same two categories of pitchers (less extension and more extension) and looked at their rate of swinging strikes with fastballs. Again, the greater the extension (and the greater velocity) the greater the rate of swings and misses:

With curveballs, Trackman found the faster they spun the more difficult they were to hit:

Curveballs with a high spin rate are roughly 50 percent harder to hit than curveballs with a low spin rate. What also is interesting is that some preliminary data suggests high spin rates also make fastballs harder to hit. Pitchers who don't throw hard but have high spin rates on their fastball -- such as Shaun Marcum of the Brewers and Koji Uehara of the Orioles -- post higher strikeout rates than their modest velocity would otherwise suggest.

Think about how revolutionary this technology can become in scouting and player development. Clubs can have data, not opinion, on pitchers with "hop" on their fastballs as well as those with curveballs that are more difficult to hit because they spin faster. In fact, Trackman already has collected data at the Area Code Games, an annual invitational of top high school talent, as well as the Arizona Fall League. It's easy to envision a day soon when "effective velocity" and "spin rate" become routine parts of the scouting vernacular.