To make room on the roster Wednesday, the Seahawks waived running back Terrence Magee.
Spiller, 29, appeared in 13 games with the New Orleans Saints last season. He was inactive in Week 1 of this season and then released. Spiller spent the first five years of his career with the Buffalo Bills.
The Seahawks have suffered multiple injuries at running back this season. Thomas Rawls (fibula) is expected to be out several weeks. Third-down back C.J. Prosise is dealing with a hand injury and won't be fully healed for three more weeks, coach PeteCarroll said.
Spiller has averaged 4.9 yards on 704 attempts in his career. He also has 192 catches for 1,434 yards.
Last year, Spiller carried 36 times for 112 yards (3.1 YPC). He caught 34 balls for 239 yards.
Spiller likely compete immediately for playing time as the Seahawks' third-down back.