Meyers (ankle) doesn't carry an injury designation for Sunday's game against the Jaguars after returning to a full practice Friday, Paul Gutierrez of ESPN.com reports.
Raiders head coach Antonio Pierce said Tuesday that O'Connell (knee) is "trending upwards to play" Sunday against Jacksonville, Tashan Reed of The Athletic reports.
Mattison took over for injured starter Sincere McCormick (ankle) in the second half of Monday's loss to the Falcons, finishing with 24 rushing yards (one fumble lost) on seven carries while corralling two of four targets for three receiving yards.
Meyers had five receptions (on nine targets) for 59 yards while getting sacked for a 10-yard loss on his only passing attempt in Monday's 15-9 loss to the Falcons.
Ridder completed 23 of 39 pass attempts for 208 yards, one touchdown and two interceptions while rushing five times for 28 yards in Monday's 15-9 loss to the Falcons.
O'Connell (knee) is inactive for Monday night's game against the Falcons, but he's available as the Raiders' emergency third quarterback behind Desmond Ridder and Carter Bradley.
Ridder is expected to start Monday's contest against the Falcons with Aidan O'Connell (knee) seemingly a game-time decision, Adam Schefter of ESPN reports.