On this week’s edition of Sharing Sox, Will and I had the privilege of having as our guest Dr. Alan Nathan, professor emeritus of physics at the University of Illinois and by all accounts the world’s foremost authority on the physics of baseball.
Nathan is entertaining as well as extremely informative, but it’s pretty long and many of you may not have time to listen to the whole program, which gets to the very basics of things like how baseball spin works and what Magnus force is, how baseballs are made, and what can be done regarding the baseball and handling of it to improve the game (or keep it from deteriorating further). So I’ve extracted some of the ideas Nathan presented and shortened things up for those who want to read what he had to say instead.
Our discussion had three basic areas: spin and goo gunk, the ball, and his ideas for getting rid of the Three True Outcomes and back to balls in play, defense, and baserunning — fun instead of boredom.
First, a confession of ignorance. I had foolishly believed higher spin rates primarily benefited sliders and curve balls. Actually, said Nathan, it’s 4-seam fastballs thrown up in the zone. That’s a more common strategy these days, because high fastballs are nigh on impossible to hit with a big upward swing to produce a high launch angle, making homers off of them rare. Goosing how much they move — or, defy gravity — is a big factor in reducing offense.
So, will enforcing rules on the gooey gunk that helps pitchers increase how much backspin they get on fastballs make much difference? Nathan is sure there will be some impact, but he’s not certain how much. We’ve already seen spin rates drop pretty much across the board, but he thinks the difference may end up being about 5% or so (Dylan Cease had a drop of more than 10% on Tuesday, but he may be an extreme case).
Nathan’s best guess is the lower rates will reduce vertical movement by half-inch to an inch, enough to reduce strikeouts. but not enough to greatly increase hard contact. He added that there’s just not enough data to work with yet.
The 2021 Harry Chadwick Award winner for contributions to baseball research says what impact rule enforcement has may be minimal in warm weather, when pitchers can get a nice, solid grip with a legal combination of rosin and sweat, but increase a lot in cold weather, when normal perspiration on hands disappears. That means we may not know the full impact of rule enforcement until at least late September ... making it a big factor in the postseason.
Instead of all the strange enforcement methods MLB has decided on, with the resultant issues (not to mention occasional rage), Nathan likes what the Japanese leagues do. They coat all baseballs with a tacky polymer, enough to give a good sound grip, but not enough to make the ball stick to the catcher’s chest protector. It’s hard to say whether that would reduce spin enough to cut down strikeouts much, but it would keep the balls, and thus the chances of success, the same for everyone. It would also relieve umpires of the pregame task of rubbing balls with Delaware River mud.
Nathan is an advisor to MLB, and was on the 2019 committee that studied just how the baseball itself was involved in the huge surge in home runs. He’s convinced MLB had never intentionally juiced the ball because of declining offense, but that the ball itself was a major factor in the power increase (launch angle obsession being another) for different reasons.
The committee toured the Costa Rican plant where Rawlings makes major league balls, and he was impressed with the precision of the manufacturing process — up to a point. Actual baseball specs, which go back to 1934, are pretty lax — 9´´ to 9.25´´ in circumference, 5 to 5.25 ounces — but he says Rawlings had made the size and weight much more consistent than required. Same for elasticity.
Then we get to the problem. The core, the windings, and the two peanuty cover pieces are all machine-made, but the seams are done by hand — a couple hundred people were busy sewing seams when the committee was there. And the seams weren’t all they seemed.
Nathan says that has led to a great deal of variance, or at least enough to make a big difference in how far a ball travels. He doesn’t see a reasonable way to convert the seam-making to a machine process, but he does think MLB should experiment with a solid cover that has seams stamped into it - the sort of ball often used in batting cages. That could keep the balls more consistent, and the height could be adjusted as needed to balance pitching and hitting.
That imbalance is, of course, a huge problem these days, a problem compounded by the fact that changes made to the ball to reduce homers — be it weight, circumference, or the drag factor of seams — may not simultaneously reduce the number of strikeouts, and may even increase them.
So, what’s to be done?
Strangely, the renowned physicist doesn’t reach to physics for the answers. He was a baseball fan before a scientist — of the Red Sox in whose turf he grew up, but we all make mistakes — and sees the best answers in the rules.
Nathan is a supporter of restrictions on infield shifts. such as are being experimented with in some minor leagues this year — two infielders on each side of second, no infielder on the outfield grass (I can see teams extending the dirt another 30 feet, can’t you?). He thinks that would make line drives the key to success again, and stop all but the big power hitters from praying to the god of launch angles and ending up with a big K — thus more balls in play, more offense, more fun.
On the physics side, he says as more teams employ humidors for ball storage, there should be a more consistent baseballs to throw and hit.
We actually discussed why swinging upward at 23 degrees is definitely not the best way to launch a ball at 23 degrees and get it to land in Row F — and the better way would greatly reduce strikeouts — but you’ll need to listen to the podcast for that ...