Silva, 6-0, 206, went to training camp with Baltimore as an undrafted free agent out of Hawaii and spent part of the season on the Ravens' practice squad. He had seven tackles in the preseason. At Hawaii, he intercepted 14 passes.
The Cowboys needed to sign Silva after Church's right shoulder popped out twice in Sunday's loss to the New York Giants. Church was replaced by Danny McCray, who did not practice last week because of a high left ankle sprain.