Sorry guys. Dumb question from an American.
When Arsenal plays in the Premier League and the Champions League are they playing the same players? How large is the rosters?
Hey man its not a dumb question! Basically the squad size (what you call roster) for the premier league is up to 25 I believe, and they have to pick the best 21 for a champions league squad, so yes the same team plays both in the Premier League and Champions league, however some rotation will take place if against an easier opposition. This is all off the top of my head so I don't know how correct it is haha.
Thanks guys - lots to learn!