This can be an easy answer but there has to be an explanation behind it. So, the easy answer is no, steaming a glove won’t physically hurt it; however, steaming a glove isn’t always necessary.
The only reason to ever steam a glove is to make the break in process go much smoother and generally much faster.
When buying a high end glove you are paying for better leather in general so steaming a glove can actually take that high end glove and soften it enough to almost make that leather not hold its shape.
Last thing we want is a $200 glove to feel like we ran over it with a car. We want a glove to be broken in certain areas, like the heel creases, but not the whole glove. You don’t want to be able to roll the fingers of the glove up like a magazine.
So if you are a youth player (12 to 13 years old) who’s ready for a nice glove but doesn’t have the hand strength yet, then steaming it won’t be a terrible idea. Getting that extra needed break in help is sometimes justified.
However, If you are a stronger college player or professional player, steaming a glove may just make the leather feel too soft and “ruin the feel of the glove”.
Although the leather itself isn’t ruined, the rigidity of the glove may be compromised for players with stronger hands.
Opening and closing the glove shouldn’t be that easy. Catching a ball shouldn’t change the shape of the glove.
We have all seen the old dad glove laying on its side helpless with its lazy demeanor, flimsy in its nature. That glove has seen better days, just not of late.
So will steaming a glove hurt the leather of the glove?
The answer is no.
Can it hurt the feel of the glove?
The answer is yes, it can under the right circumstances.
So, if at all cost avoid steaming a glove. Take the time necessary to break it in. If the perfect storm of a younger player is running out of time from the season's opening day, then I would say go ahead and steam the glove. It may just be exactly what you need.