The Cubs selected Conforto's contract from Triple-A Iowa on Wednesday.
Chicago had already informed Conforto a few days earlier that he had secured his spot on the Opening Day squad, but the team officially cleared room for him on the 40-man roster Wednesday by placing left-hander Justin Steele (elbow) on the 60-day injured list in a corresponding move. With Seiya Suzuki (knee) on the 10-day IL to begin the season, the left-handed-hitting Conforto should have a clear path to making regular starts against righties as either a designated hitter or corner outfielder.