The Lions are signing cornerback Asa Jackson off the Ravens’ practice squad, a source tells Mike Garafolo of NFL.com (on Twitter). Jackson will take the place of nickel corner Quandre Diggs who was lost for the season this week. 
Jackson played under Teryl Austin in Baltimore when Austin served as the Ravens’ defensive backs coach. Now the defensive coordinator for the Lions, Austin put in a good word for Jackson. The Ravens waived Jackson ten days ago to make room for tight end Nick Boyle and re-signed him to taxi squad. That move allowed the Ravens to keep Jackson in the fold, but it also allowed him to get scooped up by rival teams.
Jackson, 26, has had multiple stints the Ravens. The former fifth-rounder has 18 career games on his resume and he’s totaled 30 tackles and three passes defended in that time.
Detroit’s pass defense has been among the worst in the NFL this year, and in fact ranks dead last in passing DVOA, according to Football Outsiders.