Adding Brock should boost the depth of a Titans secondary that has been hit hard by injuries.
Titans coach Mike Vrabel has said an injury update on Jackson will come Wednesday.
The Titans already placed cornerback Malcolm Butler on injured reserve Nov. 5 after he hurt his left wrist.
Brock played 10 games for the Cardinals this season and had 37 tackles.
The 6-foot Brock has played 113 games over 10 seasons in the NFL with the San Francisco 49ers, Minnesota Vikings, Denver Broncos and Arizona. He has 11 career interceptions and 246 tackles.
The Titans (7-5) have won three straight heading into Sunday’s game at Oakland (6-6).