Arauz made the Red Sox's Opening Day roster, Ian Browne of MLB.com reports.
The Red Sox opted to keep Arauz, a Rule 5 selection in the offseason, instead of more established infielders and prospects the organization has cultivated. The Red Sox must maintain Arauz on the active roster (barring injury) for the entire season or offer him back to the Astros. It's easy enough to carry Arauz the first two weeks, when rosters are expanded to 30 players. The team will be challenged to keep him when rosters are trimmed to 28 on Aug. 6, then down to 26 on Aug. 20.