Gruden discussed Galette’s status on Thursday, a day after the pass rusher was injured toward the end of practice.
Gruden says Galette is scheduled to have surgery Friday.
Galette had missed Washington’s first two exhibition games as he worked his way back from an injury to a chest muscle.
He is the fifth Redskins player lost to a season-ending injury in the preseason, including tight ends Niles Paul and Logan Paulsen.
Washington signed Galette at the start of training camp after he was released by New Orleans because of off-field issues. He had 22 sacks for the Saints the past two seasons.
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