You can't though. Maybe at the most 1 thread on every football night, one on college games, one on your high school team (for those who play) but when it's a boring season and nothing's up; it will die.
Honestly, baseball season is shit I don't care if anyone likes it. A shit load don't and no one's gonna do anything just a way for spam. Use off-topic. Look at those threads they are extremely general and get a max of 3 pages.
A sports board is added on every new forum that people try to create. It never goes anywhere. There's not enough demand and content that can fit into the section.