Copying @pj on this response too since he has the Red Sox as well.
The rainout rules work as follows. If a game is cancelled due to rain and not replayed that week if that game matters to the overall week then it will be decided by run differential for the week.
So currently the Red Sox and 1-1 with a rain out. They have 3 games remaining this week against the Padres.
if they go 3-0 or 2-1 against the Padres you are in the clear
if they go 0-3 you get a strike
if they go 1-2 they will have a record of 2-3 for the week but also a rainout so it goes to a tiebreaker which is run differential for the week. If the team has a 0 or positive run differential for the week you are in the clear. If they have a negative run differential for the week then you get a strike. So technically you could still move on if they went 1-2 but probably unlikely considering their run differential is currently -4 for the week.
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