Thirty-one days.
At the time Major League Baseball rosters expand from 25 to 40 players on Friday, that's the number of days of baseball remaining in the 2017 regular season. You've got 31 days to make your final push toward a league championship.
For some, Friday -- or at least a date within a few days on either side of it -- means your league's trade deadline. It's also three days shy of the start of head-to-head playoffs in ESPN leagues. Whatever your league's setting, it's as good a time as any to get your roster ready for the final push.