Recently, San Francisco Giants left-hander Randy Johnson announced his retirement, ending a long, successful, peripatetic career. It seems silly now, but there was a time when he so struggled with his control that he was a guy who was considered a high-risk prospect. Enough so that he was not the main guy in the trade that brought Mark Langston from Seattle to Montreal (look up Brian Holman).
Johnson now is a guaranteed Hall of Famer; second all-time in strikeouts. More than 300 wins.
In reading about Johnson, one often sees comments about his being a hard-throwing lefty, with frequent comments about the stereotype of left handers being soft-tossers who get by on guile and trickery. What serious baseball fan is unawares of the phrase "crafty left-hander?" There has been no shortage of lefties who had long, even successful careers who seemed like their fastballs would not break a window pane. Randy Jones won the 1976 Cy Young award, for example. Jesse Orosco pitched until he was 100. Frank Tanana had a very long career with a fastball that would not bruise a baby's butt. That's not entirely true of course; Orosco was only 72 when he retired, and a lot of people forget that at the start of his career, Tanana had a good fastball.
Johnson certainly went against the common thinking, which of course, is frequently wrong.
But why does this perception exist? ARE left hand pitchers more likely to have less than blistering fastballs?
Of course, only a real analysis would reveal the truth, but here is a thought. There certainly is a tremendous bias in big league scouting for guys who can throw hard. For the most part, this bias is useful - a pitcher who can only throw 82 mph had better have some extra-ordinary other talent. All else being equal, the guy who can throw 95 is going to have a much better career than the guy who can only throw 88.
But looking at the distributions I think reveals something. Demographic and epidemiological data show that in the US, about 11 per cent of the population (one in nine) is left-handed. If this were to transfer to major league rosters, a standard pitching staff (10 pitchers) would have about one lefty. This is not the case. Usually, a roster will have at least one starter, one "left hand specialist," and one other left hand pitcher. A cursory look at the rosters reveals that left hand pitchers have about a 300 per cent premium to their value versus right handers.
To see this effect, look also at the roster of outfielders (infield is a biased sample, since there are NO left hand throwers playing any of the positions other than first base for obvious, physical reasons), and compare the percentage of left hand throwing outfielders to left hand pitchers.
What is the implication?
In order to fill the rosters with lefties, teams have to go deeper into the talent pool. Guys who if they were not left-handed would have quit baseball and taken up work elsewhere are on big league rosters. That means a lot of pitchers with mediocre, or worse, fastballs.
Put simply, pitchers like Randy Johnson seem like exceptions to the rule because there are a lot more guys on rosters like Scott Schoenweis than guys like Doug Jones.