Against the Cardinals, both filled in nicely after Jones suffered his injury in the first quarter.
The Seahawks rushed for 164 total yards. Forsett carried 17 times for 123 yards, including an 11-yard score, while Rankin chipped in 24 yards on three carries. The two also combined for eight receptions for 50 yards, with both regularly making defenders miss in open space.
"Those guys did some good things (Sunday) running the ball," Seahawks coach Jim Mora said. "They looked explosive."
A seventh-round draft choice last season, Forsett, 24, showed glimpses of his special running ability during the 2008 preseason, rushing for 248 yards, including a 15-carry, 136-yard performance against Chicago. However, at 5-foot-8, 194 pounds, there is some question about his durability as an every-down back in the NFL.
"He's got good balance," Mora said about Forsett. "You look at a guy like Maurice Jones-Drew, some of those guys that are shorter in stature, that have a lower center of gravity, they don't go down as easily. They seem to bounce off things a little bit more. He runs compact. He's just got to keep getting better. We've all got to keep getting better. Hopefully he can find some holes this week again."
Rankin, a 6-foot-1, 205-pound 24-year-old from nearby University of Washington, was signed by Seattle when Oakland cut him earlier this season. He's also being used as a kick returner, and he has continued to impress Mora with his speed through the hole.
"Louis did some good things catching the ball and running the ball," Mora said. "We'll continue to involve him in both the pass game and the run game."