The 22-year-old Miller is a rookie free agent out of Florida International. He had 33 tackles and two interceptions in nine games as a senior.
The 5-foot-10, 190-pound Miller was with the team earlier this offseason on a tryout basis at Buffalo's mandatory minicamp.
To make room for Miller, the Bills released cornerback Michael Carter. Carter originally joined the Bills as a free agent in May.
The moves were announced on Sunday.
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