The fact that R.A. Dickey isn't starting the All-Star Game has nothing to do with merit, and everything to do with legitimacy.

Even though he's statistically the best pitcher (player?) in the majors this year, the source of his greatness — the knuckleball — makes him a second-tier player in the eyes of the baseball world.

It's not just baseball's fault.

All sports have entrenched assumptions about what an excellent player looks like.

In the NBA, an excellent player is a scoring wing who makes difficult shots.

In the NFL, an excellent player is a pocket-passing quarterback with a cannon arm.

And in baseball — a sport obsessed with its own traditions more than any other — an excellent pitcher is a hard-throwing right-hander with a wicked breaking ball that strikes a lot of people out.

It's not enough for Dickey to be 12-1 with a 2.40 ERA. He has to be 12-1 with a 2.40 ERA in a very specific way.

The baseball world sees Dickey and his knuckleball as a gimmick, an odd and fleeting path to effectiveness that automatically disqualifies him from the realm of great pitchers and places him his own separate and inferior category.

And the anti-Dickey bias includes one other key assumption: this won't last.

Knuckleballers are historically streaky, and that allows the baseball world to write off his greatness as a stroke of luck. It allows people to de-legitimize him under the assumption that his greatness doesn't come from some innate skill.

Of course this is a lie because any player, no matter how he plays, can suddenly "lose it." Just look at Tim Lincecum — who was once in the "great pitcher" category that Dickey isn't allowed to be in. Lincecum was the archetypal great, hard-throwing pitcher, but his greatness didn't last. It can happen to anybody.

The basic lesson is this: Greatness in sports is not about objective superiority, it's about satisfying popular assumptions about what greatness ought to look like.

There's an inherent bias against players who succeed differently. Michael Vick was only accepted as a great player when he starting throwing more from the pocket in Philadelphia. Greg Maddux is considered a tier below Roger Clemens and Nolan Ryan because he didn't throw hard. And the world didn't finally accept LeBron James as a great player until he "took over" games in the 2012 Playoffs.

Dickey, despite his historic season, just doesn't look the part.