Running back Tim Hightower lost a fumble on his sixth carry on Sunday, and he didn't get a chance for a seventh attempt.
Beanie Wells replaced Hightower, who touched the ball just one more time - via the pass, in the Cardinals 22-10 loss to the Seahawks.
It was the fourth fumble Hightower has lost this season, and it could well be the one that costs him the starting job.
Like most of Hightower's fumbles, the one Sunday came at a critical time. Down 3-0 in the second quarter, the Cardinals were gouging the Seahawks with the run. Hightower had gained 24 yards on his previous carry and had gained 13 yards before he fumbled.
He finished with six carries for 59 yards.
"We can't live with that going forward," Whisenhunt said. "Momentum was starting to turn. We were moving the football."
Hightower said the ball just slipped out.
"It was more me than them," he said. "It hurts a lot. We needed a big play, we needed momentum, we needed something. Our defense was playing great. They are playing too good for us to do stuff like that."
Beanie Wells was already getting a majority of carries. Hightower is still a pass-catching threat who could see third-down work though. This appears to give Wells' value a boost, but without much of a passing game teams can look to shut down the run so he's only a safe play in certain matchups.