What are numbers in parenthesis next to your team in the weekly matchups section? Have a good idea of what they might be but don't want to assume.

that's how much that team is favored to win by according to the game.

Example 1:
Houston @ Tennessee (-4)
That means Tennessee is favored by 4 points

Example 2:
Houston (-4) @ Tennessee
That means Houston is favored by 4 points.

How is that calculated?

I don't know the exact formulas involved, but it probably works similar to how the game generate power rankings, which includes part of the previous season's stats until around week 8.

If it were me creating the formula I would probably look closely at Points For (PF) and Points Against (PA) as well as the strength of the opponents played. There's so much that could go into the formula though. JDB is probably the only one who knows it.

From the forums, it says it is PF/Game, PA/game and then subtracted. Its why you could have possible 0-12 team vs 1-11 team as GOW.

https://usflwfl.myfootballnow.com/community/thread/1/3156?page=1#21490

ah, well, that's a very basic formula. I was expecting something more involved to calculate the spread.

Game of the week is just whatever game has the lowest spread though and I like it. Sometimes those 1-11 vs 2-10 games are fun.

There is also an artificial cap on the spread at 14 points.

Also, 1-11 vs 2-10 may turn out to be a fun game to watch, but it doesn't deserve to be hyped as the "Game of the Week".

Strangely does not show in user created leagues

It must be an option. It's in other user created leagues.

It will only appear after Week 1 is completed.