Bunkley took a $3.15 million pay cut this offseason to help the Saints get under the salary cap.
Byrd is returning from a season ending knee injury. Colston has a non-disclosed injury.
All four are still on the roster and can be activated at any time before the start of the season.
The physical was necessary because Galette missed time during OTAs and all of minicamp with a pectoral injury, which Galette downplayed. Galette will not pass through waivers and will be free to sign with any team.
Charges against Galette had been dismissed after his January arrest for domestic violence. A video had also surfaced in which a man identified as him by a league source was shown striking a woman with a belt during a brawl in 2013.
"(It was) the worst call they've ever made," Gatlette told the New Orleans Times-Picayune about his release. "It was a terrible call to kick me when I'm down."
Galette has certainly proven productive on the field with 22 sacks over the last two seasons combined.
Galette, who also dealt with a pectoral injury this spring and summer, totaled 22 sacks over the last two years combined. He played in all but four games for New Orleans since the 2011 season.