The Ducks announced the moves Tuesday.
The 21-year-old Rakell has struggled offensively after making the Ducks' opening-night roster out of training camp. The former first-round pick has no goals and three assists in 17 games for the Pacific Division leaders.
Blacker made his NHL debut last Friday against Chicago for the Ducks, who have five defensemen out with injuries.
Anaheim has trimmed its roster of unproductive young players in recent days, no longer willing to wait for them to earn regular NHL roles.