Whoever they start Saturday is the one they view as #1. The way they've set it up it looks like they are favouring Scrivens.
Carlyle said they'll have to earn each game. Scrivens got the start because he had a better camp (and probably benefitted from being in game shape for months before camp even started). I suspect that Reimer didn't necessarily earn this start based off practice but rather got the start because it's a back to back situation for the team. In many cases, the guy you start on opening night is your starter but in many cases, teams already have that figured out. The Leafs don't so who started on Saturday matters little. Each start will have to be earned based on how they play during games and during practice.