The hiring isn't a surprise as The Baltimore Sun had previously reported Austin was expected get the job.
Austin had been the Ravens' secondary coach for the past three seasons, ranking 12th against the pass last season, 17th in 2012 and fourth in 2011.
The Lions also announced that offensive line coach Jeremiah Washburn remains in place as offensive line coach. That could close out Ravens offensive line coach Andy Moeller from a position with them at this time. Moeller had been under consideration from new Lions coach Jim Caldwell, the former Ravens offensive coordinator.
Austin worked previously for new Lions coach Jim Caldwell, the outgoing Ravens offensive coordinator, at Wake Forest. He was on the Penn State coaching staff with Caldwell before working at Wake Forest.
Austin played safety at the University of Pittsburgh when Ravens coach John Harbaugh was on the staff as the tight ends coach.
The Ravens now have job openings at offensive coordinator, running backs coach after parting ways with running backs coach Wilbert Montgomery, secondary coach and quarterbacks coach with Caldwell previously operating in a dual capacity coaching the quarterbacks and coordinating the offense.
Senior defensive assistant Steve Spagnuolo has a background coaching several positions, including defensive backs.
The Ravens also have defensive assistant Matt Weiss on the staff. Weiss has worked in quality control and with the defensive backs since joining the staff in 2009.