It's just a making conversation question. Totally agree that injuries need to be addressed and not ignored. That said, what it a player had a slight fever (99.7?) or had the runs or had a really bad sore throat? Something that a motrin or imodium could address? Yet, the player instead told the coach "I have to sit out today." Is that a mark against the player?
(BTW @GoingwiththePitch book made me think of the question because there was one time he was very sick with fever and stomach issues but he still played in the game.)
It's an interesting question. To the original question of "How important is it to keep your mouth shut, stay out of the trainer's room, and play with nagging injuries" yeah that's in the back of players minds. Players want to play and they don't want to give up their opportunity to someone else.
I tell every athlete that comes into the athletic training room that if you play a full competitive season you're not going to be 100%. That's not an accurate expectation. But I'd like to know about something that is bothering them. They don't have to tell me everything, and I'm not exactly going to be telling the head coach every time so and so came in unless they ask or it's important. Example: an OF comes in, back is a little sore, not really painful or anything, and they heat it for 10 minutes and they're okay. Probably not going to text the coach that so and so came in for a heat pack.
The player, at the level, isn't going to just say, "Well I have to sit out today," they're going to say "Go see the athletic trainer and then we'll decide," if that makes sense?
As for the niggles/aches and soreness leading to injury down the line (which could be a logical thought process) we don't have that information for baseball players. We do for semi-professional soccer players: https://www.tandfonline.com/do...6?journalCode=rsmf20 and the infographic for it: https://twitter.com/FigtreePhy...197315842049/photo/1 which basically, the players that had a non-timeloss injury within 7 days or less were more likely to get hurt and experience a time loss injury in that 7 day window. But again, that data for baseball players isn't available.