The Dolphins promoted safety Montre Hartage from the practice squad Saturday.
They waived cornerback Xavier Crawford in a corresponding move.
It marks the first time Hartage has appeared on the 53-player roster. The Dolphins signed him as an undrafted college free agent and waived him in the final roster cutdown.
Hartage played collegiately at Northwestern, where he earned first-team All-Big Ten honors last year.
The Dolphins claimed Crawford off waivers on Oct. 29. He appeared in one game with the team but did not record any stats.
He entered the league as a sixth-round pick of the Texans this past spring. Crawford played four games for the Texans.