Coach Pete Carroll says the hope remains Hasselbeck will be able to play Sunday against the New York Giants. Hasselbeck will attempt to pass the league-mandated concussion testing and practice Thursday, Carroll says.
Hasselbeck was injured in Sunday's 33-3 loss to Oakland, although he played until the final series of the fourth quarter. He completed just 13 of 32 passes for 160 yards and was sacked eight times.
Carroll says Charlie Whitehurst will get most of the practice reps with practice squad quarterback Zac Robinson also getting a turn.
Martin was with the Seahawks during training camp but was part of Seattle's final roster cut following the conclusion of the preseason.
Richardson spent the past three seasons with the Oakland Raiders. He was a fifth-round pick of the Raiders in 2007 and has 109 tackles and seven sacks.
White spent the past three seasons with Houston, but entered the league in 2005 with Green Bay.
The Associated Press contributed to this report.