"Trying to hit Phil Niekro is like trying to eat jello with chopsticks. Sometimes you get a piece but most of the time you get hungry."

-Bobby Murcer, on hitting a knuckleball

It's an unpredictable pitch that puts virtually no stress on a pitcher's arm.  Hitters have all sorts of difficulty timing the pitch.  It can be thrown by virtually anybody, and those who learn to master it enjoy big league careers well into their forties. 

So why don't more pitchers throw the knuckleball? 

This is a question recently posted by Jim Caple of ESPN, who is one of many sportswriters marveling over the success that knuckleballer R.A. Dickey is having with the New York Mets this season.  Dickey adopted the knuckleball five years ago as a way of salvaging his baseball career, and his mastery of the pitch is to the point where he has a terrific case for being the Cy Young Award winner in the National League this fall.

So why don't more pitchers take the R.A. Dickey path to stardom?  Well, it's much easier said than done:

1.  It takes a long time to master, and it is hard for coaches to trust.

Pitchers cannot learn to throw the knuckleball overnight.  The pitch requires a special grip and throwing motion, and it can often take years for a pitcher to get it under control. 

Pitchers who throw the knuckleball also tend to get their careers going at an advanced age when compared to other pitchers.  Dickey, who was originally drafted by the Texas Rangers in 1996, bounced around the organization for years before finally deciding to take up the knuckleball on a regular basis in 2007.  Four organizations later, Dickey found a spot in the New York Mets rotation for the 2010 season.  At age 37, Dickey is finally starting to enjoy his prime.

His story is not uncommon among knucklers.  Hoyt Wilhelm was nearly 30 years old when he made his MLB debut.  Charlie Hough did not reach the big leagues for good until he was 25, and he was not trusted with a regular spot in the rotation until he was 34.  Tom Candiotti did not find a regular spot in a rotation until he switched teams at age 28.  Tim Wakefield lost the confidence of the Pittsburgh coaching staff and was out of the Majors for a year before resurrecting his career in Boston at age 28.  Even Phil Niekro, who built a Hall of Fame career out of throwing a knuckler, did not become a regular starting pitcher until he was 28. 

2.  Other pitches are more difficult.

Pitchers who throw the knuckleball often must do so on almost every single pitch, and they tend to not throw that pitch very hard.  If they are unable to do so, the knuckler becomes very easy to lay off while other pitches become very hittable.  Wilhelm and Wakefield relied almost exclusively on the knuckleball, utilizing fastballs almost as off-speed pitches to keep hitters guessing.  An additional downside is that if the knuckleball is not dancing, it becomes a batting practice pitch for big league hitters.

3.  It is tougher on catchers.

The Red Sox had to keep Doug Mirabelli on the roster as his personal catcher during much of Wakefield's tenure in Boston, as regular catcher Jason Varitek wanted no part of handling Wake's unpredictable pitch.  This would not be as big a deal if, say, the Red Sox had several knuckleball pitchers on their staff.  But Wakefield was the only one (heck, he was pretty much the only one in baseball), and this meant that the Red Sox had to waste two roster spots for the needs of one player.  This also made it difficult for the club to pitch Wakefield in relief, thereby limiting the knuckleball's advantage of being a low-stress pitch.

4.  It is seen as a last resort.

Pitchers who turn to the knuckleball often do so because they have no other options.  Almost all knuckleballers first attempted to become successful pitchers via conventional means but suffered setbacks (often injury-related) along the way.  Hough, Candiotti (an early recipient of Tommy John Surgery), Wakefield, and Dickey all fall into this category.  As a result, very few pitchers become dedicated knuckleball pitchers at a young age.

Perhaps this last point will change in the near-future.   Dickey's success figures to inspire more youngsters to take up the pitch on a fulltime basis.  We have seen it happen already:  Eri Yoshida, who was inspired by Wakefield to learn how to throw a knuckleball with a sidearm motion, became the first female ever drafted by a Japanese professional baseball team (at age 16, no less) and has since played in the independent leagues in North America.

Who could be the next youngster inspired to learn the knuckleball?