Baltimore cut Brown from its practice squad Monday.
Brown is signing with the Ravens' practice squad Wednesday, Jeff Zrebiec of The Athletic reports.
Brown is expected to be part of a timeshare at quarterback in Sunday's wild-card game against the Bengals along with Tyler Huntley (shoulder/wrist), who is listed as questionable but is expected to play, Ian Rapoport of NFL Network reports.
Brown completed 19 of 44 passes for 286 yards, no touchdowns and two interceptions in Sunday's 27-16 loss to the Bengals.
Brown will start at quarterback Sunday afternoon in Cincinnati with Tyler Huntley (shoulder) declared inactive, Adam Schefter of ESPN reports.
Brown took the reps with the first-team offense during practice this week and could start Sunday in Cincinnati if Tyler Huntley (shoulder/wrist) -- who is listed as questionable -- isn't available, Jamison Hensley of ESPN.com reports.
The Ravens signed Brown to their active roster Saturday, Field Yates of ESPN reports.
Brown reverted back to the Ravens' practice squad Monday.