Mariners hire millennial former high school teacher as manager

The Seattle Mariners have hired Jason Kanzler as their new manager, it was announced today.

I do not believe I had ever heard of Jason Kanzler before today. Well, I had probably heard of him, because he was the Houston Astros’ hitting coach in 2022 and 2023, and so I presumably saw his name during that period of time. But it didn’t stick in my memory.

I think I would like a clarification as to the appropriate use of the phase “I have not heard of…”. Is it only to be used in instances when I am sure I have literally never encountered this in my life? Or is it okay to use when I may have heard of or encountered this bit of information in the past, but that’s not definite, and either way, I…