Galette's agent, Alvin Keels, told The Associated Press on Friday that Galette, whose 10 sacks led the Saints last season, would be released Monday if he passed a physical over the weekend.
The Saints apparently were concerned about NFL reviews of Galette's actions off the field, including a domestic violence arrest for which charges were dropped and a video of a beach melee that appeared to involve the player.
The Saints also waived center Michael Brewster, citing a non-football injury.
The 20-year-old Brock has played in 20 games with Buffalo, Kansas City and Cincinnati since 2011.
Manhart, a rookie out of Nebraska-Kearny, plays guard and center.
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