Gregory may or may not make the regular-season roster, but his presence in the meantime will be welcomed by a team that has likely lost backup Sanders Commings for the season. Commings will have surgery to repair a broken ankle Thursday.
Starting safety Eric Berry left practice early with a sore ankle but his injury isn't serious and he could return to practice as soon as Friday.
Even with Berry, the Chiefs are perilously thin at safety. Husain Abdullah is the other starting safety. The backups are Jerron McMillian, who played two seasons as a backup for the Green Bay Packers, and two developmental players, rookie Daniel Sorensen and Malcolm Bronson.
So a veteran body like Gregory comes along at a good time. The 5-foot-11, 200-pound Gregory played six seasons for the Chargers and two for the Patriots. He started in more than half of his team's games in the past three seasons.
To clear roster room for Gregory, the Chiefs waived rookie linebacker Ben Johnson, an undrafted free agent.