If you're even a casual baseball fan, that second question—why don't more pitchers throw submarine style?—might seem preposterous. Submarine pitchers, whose release point is so low their knuckles practically scrape the ground, are a rare breed in Major League Baseball. And why shouldn't they be? An overhand windup is not only iconic and powerful, it's also the natural movement when playing catch with a ball.
But there was a time when all the pitchers threw underhand. It was any year before 1872 and it wasn't because our ball-playing forefathers had yet to master the more masculine-seeming motion, but rather because it was written into the rules.
"The rule was that your arm had to be perpendicular. Straight underhand until 1872," MLB's Official Historian John Thorn says. If you think that sounds unfair to the pitchers, who were forced into a relatively unnatural throwing motion, you'd be correct. In fact, that was sort of the point.
"The pitching motion was different because the role of the pitcher in relation to the batter was different," Thorn says. "He was not regarded as someone who was in mortal combat with the batter. His purpose was the serve up pitches that the batter would then put in play, because what the audience liked to see was fine fielding plays and lots of base running."
Of course, it didn't take long for pitchers to realize that by inching up their release points past the legal limit they could give their team a competitive advantage. In 1872, the rules caved to accommodate the trend and began permitting a side arm release. But given a few inches, the pitchers took, well, a few more inches and continued to raise their release points in opposition to the written rules. Another concession by the League presidents allowed for straight pitches from the shoulder until 1883 and 1884 when all restrictions on pitching style were abolished in the two leagues.
Not everyone switched their style right away. Most submariners stayed submariners. But as the space between the mound and home plate increased from 45 feet before 1880 to the current 60 feet 6 inches, new pitchers found that the overhand style made it easier to control the ball over a greater distance.
What's more, throwing overhand allows for more sophisticated breaking pitches. "Your curveball with the underhand or sidearm delivery tends to be the schoolboy curve, which any Little Leaguer can throw. It breaks laterally, not down," Thorn explains. "At the collegiate and Minor League and Major League level, curveballs break in two directions—both laterally and down."
If early pitchers knew a higher delivery granted them a competitive edge and that in practice it adds an extra dimension to your curveball, then we have arrived at our first question: why does anyone bother to still pitch submarine style?
A quick word on submarine pitching, although I have been using it interchangeably with "underhand": there is actually a slight difference in the modern version. Submarine pitchers lean their whole upper body down towards the ground but keep their hand typically on top of the ball. This is in opposition to softball underhand in which the ball is lobbed while remaining upright.
Back to the question at hand. For the most part, this has to do with the fact that, these days, almost all submarine pitchers are relievers. "As a relief pitcher, you have the tremendous advantage of five or six innings of having been thrown to conventionally by someone else so your new-fangled delivery is quite a change and it’s very hard to adjust to," Thorn explains. So what used to be the only style of pitching has now become valuable in its rarity. Try to throw that way to the same lineup more than once a game and big league batters will quickly learn to take advantage of the one-dimensional break.
But Thorn makes another claim, that "underhand is much less strain." A bold statement in a era when pitch counts drive starters from the game ever earlier and Tommy John surgery sidelines pitchers for full seasons. So let's unpack that.
I reached out to Glenn S. Fleisig, Ph.D., the Research Director at the American Sports Medicine Institute. He explains that when throwing at the same speed, say 80 miles per hour, underhand and overhand throwing put roughly the same amount of force on the shoulder and elbow joints. But submarine pitchers and traditional pitchers don't typically throw the same speed at the Major League level.
"I would say the average fastball pitcher has more force on his arm than the average sidearm pitcher in Major League Baseball, because the average overhand pitcher is throwing with more velocity," Dr. Fleisig says. But there is an important distinction between causation and correlation to be made here. "[Submariners are] throwing less hard not because sidearm is a less hard thing but because they were guys who threw less hard from over the top."
Back to Thorn to elaborate: "In many cases, these are pitchers who hurt their arms, or don’t have great fastballs so they needed something to draw the attention of scouts." And otherwise, "If a pitcher has real ability as an 11- or 12-year-old his coaches will dissuade him from throwing sidearm."
And now we're ready to tackle those Big Questions succinctly:
Why do some pitchers throw submarine style?
Because it allows struggling or injured pitchers to reinvent themselves as a valuable commodity out of the bullpen by allowing an unusual delivery to disrupt the batter's timing of the ball.
Why don't more pitchers try it?
It renders one of your pitches far too hittable for you to be a starter and, culturally, talented kids are pushed in the direction of conventional throwing to best capitalize on their athleticism.