I wouldn’t recommend any such information being made available simply to the fans. It’s a matter of public interest to make sure contracts are being fulfilled, rules regarding injured players and rosters are followed, and that the state is conducting proper oversight. In addition this information whether vital or not in your or my opinion is valued by bookies and because gambling on sports is legal the state has a further obligation to insure sports are conducted on the up and up. Public information should be readily available to the public, sports fans or otherwise. I don’t see any convincing reason why this information rightfully possessed by the public should be kept secret in some legal manner. But if it’s not information necessary to guard the public interest then it needn’t be collected at all.
No, it really doesn’t. The only way you might consider this so is if legal betting somehow required the weights, but that’s not the league’s or the player’s concern at present. Certainly, the leagues getting closer in bed with fantasy betting is clouding that, but that’s not a matter of public interest.
Besides, weights are typically only given at the beginning of a season, and never updated, so it wouldn’t give you any indication of they player’s current status. Weights in sports like football and baseball have never been updated frequently enough to be of any use in manner you suggest.
In the case of player injuries (as you mention), I can absolutely see this being an issue – and this is why leagues have rules about teams disclosing players’ injury status, and engage in disciplinary action against teams that flout the rules.
I’m just having a difficult time picturing any situation in which knowledge of a player’s weight (except for, as you note, sports in which weight is part of the sport’s actual rules) would be relevant, or give an unfair advantage to someone if it was not publicly known.
MLB Baseball lists the player’s height and weight right at the top of their stats, along with the other important stuff such as position, batting & throwing side, jersey number and age. This stuff is also at the top of a player’s baseball card back (cards are made by independent companies, not MLB).
I do think it’s weird that we all get to be so intimate with a player’s weight. But also, I listen to games almost exclusively on the radio so when the announcer is describing a guy like Triston McKenzie (6’5"/165#) his weight very helpful to get a picture of him in your mind, versus Aaron Judge who is 6’7"/282#. It’s also helpful if you can translate a guy’s body makeup to that of a similar historical player.
You kind of get a feel as to what the player should be able to do in the game based on his size. There are some big fellas who can steal a base but in general you can tell if a guy is going to be good at it based on his size, or maybe he’d be more of a home run guy. If you’re not seeing him play on TV or in person, and just reading stats, the height and weight can give you insight.
But if published weight went away, honestly nobody would notice. Even my radio announcer would merely say a guy is tall and slim, or tall and broad, and that’s about it.
Any significant change in a players weight needs to be examined. It may be the result of drug free workouts or diets and just fine, but otherwise it should be known. Rapid weight gains are often an indication of PED usage.
They list a weight on a card or program. Does it change? Was it accurate? No doubt weight is relevant to mountain climbers or combat sports, and doubtless others. In most sports, once they have reached higher levels surely many other things are more important. That said, I haven’t paid much attention to the issue. I doubt it is very relevant and in the case of sine sports might be an ego or intimidation thing.
In horse racing, do they list the weight and full health exam of the horse? There was some dude on 60 Minutes who advised people whether to buy racehorses largely on the basis of abdominal ultrasounds. Should hockey players not provide the same level of detail? 
I don’t doubt that, and I also have to believe that professional teams regularly track their players’ weights, even if they don’t publicly publish the results of those weighings.
But, OTOH, again, the weights that teams do currently publish on their public rosters may or may not be entirely accurate, much less being information that is regularly updated.
Also, I believe that all of the major U.S. professional sports leagues have a regular testing protocol for PED usage, as well, but again, unless a player fails one of those tests, and is penalized or suspended for doing so, those test results are also not public knowledge.
I want to be clear that I don’t think a lot of the weight information is necessary to record. In those cases the public interests can usually be served without recording the weight information. Unfortunately the rules and contracts have already been written without my prior approval.
Wow. Sounds like he could be carried away by a stiff breeze.
It’s a thing of beauty to watch the kid pitch!
It’s like watching an octopus do cartwheels.
Sumo. No weight classes just ranks based on winning.
I don’t know about the MLB page, but baseball cards have been known to use the same number for a players weight for the duration of their career, even though it’s visibly different.
Define “public interest”. Is it in the public interest to watch games being played? Surely we would consider it odd if there were a popular sport where the competitions couldn’t be watched. Having a private professional sport wouldn’t and shouldn’t be illegal or anything, but the fact that fans are interested is usually considered enough of a reason to let them watch.
How is this any different from the fans being interested in the basic physical characteristics of the athletes?
They do call him “Dr. Sticks” for a reason.
I thought about sumo. They say it is about technique as well as size. But those boys are big (I have seen a grand total of one match. That’s enough for me. Many elements of Japanese culture are interesting, but other things like kabuki don’t do much for me).
I have seen enough sumo matches and tournaments to know that it is not always the biggest wrestler to enter the ring that wins. There can be enough of a difference in weight that you notice it visually, and still the smaller guy wins. At the higher levels especially it is skill and not the weight that determines victory, though of course you do have to be in the right ballpark to have a chance.
Another determinant that can affect outcome but paradoxically doesn’t always is height, especially in Tennis. One of the tallest men on Tour Ivo Karlovic, has played three times against one of the shortest men on tour Olivier Rochus and their head to head is 2-1 in Rochus’ favor. On the women’s side, Justine Henin, one of the shortest players beat Sharapova, Venus and Serena, much taller players.
Knowing the height and weight give you some idea of how they would look in real life, but at a certain level I do not think that it really determines outcomes in sport.
//i\\
Muggsy Bogues played in the NBA for 14 years at 5’3”. For 6 consecutive seasons he was in the top 7 in assists, and he was top 10 in steals in 3 of those seasons. He got a double-double 146 times in the NBA. Despite his size in a league where 6’ is short, he was a valuable player who more than held his own.
I think he’s a great example of how physical stats both matter and don’t matter in sports. You would think someone as tiny as he was could not complete in a sport at the highest level where height is a critical advantage and he’d sometimes play with men 2 feet taller than he was, but not so. His skills more than made up for that. But at the same time, his best stats were things that didn’t require being tall; being small and quick is ideal for steals and assists. He was never going to be a dunking champion or put up huge scoring numbers. But he found a way to be an asset.
Skills matter greatly, but it is no coincidence that most of the athletes in a given sport look similar. Your chances of playing professional basketball double for every inch over 6’. If you are a player above 7’ your chances are dramatically better, as high as 1 in 3.
Well, in fact…Bogues won the Slam Dunk competition at the 1986 All-Star Game, with two perfect-scoring dunks in the final round. 
For soccer, yes. You want your centre backs and defensive midfielders to be bigger so they can dominate the opposition forwars physically and win challengers in the air. Your playmakers, especially on the wing are ideally, smaller and more nimble, with lots of stamina, your forwards need to be speedy guys with enough of a physical presence to at least be able to stand up to the defenders.