The Raiders (2-2) opened as four-point favorites against the Ravens (2-2), but the line has come down to 2.5 as of Wednesday morning.
Both teams opened their seasons with impressive victories before consecutive humbling losses. Carr suffered a transverse process fracture against the Denver Broncos over the weekend and will miss two to six weeks; EJ Manuel will start in his place in Oakland.
The Raiders have won their past two games against the Ravens, late-fourth-quarter comebacks each of the past two years. Before that, they had won just one of their first eight meetings.
The California setting could prove decisive. The Ravens have one win in their past six road games, against the Cincinnati Bengals in their season opener last month, while Oakland has won five straight at the Oakland Coliseum.
The over-under for the game is 40 points.