Tag System

I would like to add a tagging system that resembles that of ESPN.com (Sample Link here. Notice how Tim Lincecum’s name is linked.) for my site:

https://butthegameison.com/blog/

I would like for a tag to automatically appear for every player’s name I use instead of placing the tags at the end of my posts. The first time a player’s full name is mentioned, it would be linked to all posts using that name.

What changes or modificationd do I need to make to the code in order to have a system like this. I understand it is pretty hard to comprehend but any help is valuable.