Coach Pete Carroll said Monday the Seahawks will give Whitehurst all the snaps in practice this week in preparation for Sunday's showdown with the Rams, but he wasn't ready to rule out Matt Hasselbeck, who left Sunday's 38-15 loss at Tampa Bay after running for a 1-yard touchdown in the first quarter.
Hasselbeck suffered a strain to his lower back/hip/gluteal area that did not allow him to return. He underwent an MRI and additional tests Monday morning, and the results left Carroll somewhat optimistic.
"It's something (that) it may be manageable. It may be," Carroll said. "The MRI results were not such where he doesn't have a chance. They were very hopeful that he has an opportunity to get back, but we won't know for days.
So it's kind of a difficult situation for us, because we don't know and we're not sure what is going to happen until we find out the news probably by Saturday, or it may go all the way to game time."
After Sunday's loss, Hasselbeck said he first sustained the injury in Week 3 against San Diego and that it has bothered him slightly during the season, but never as badly as against the Bucs. Hasselbeck went to the ground after scoring and walked off the field.
If he can't go, Whitehurst would make his second career start as Seattle aims for its first division title since 2007.
"I want to make sure as we proceed through the week and know what we're doing," Carroll said. "If Matt can play a factor in that, we'll figure it out when the time comes."
Whitehurst completed 11 of 18 passes for 66 yards, with no touchdowns nor interceptions, in Sunday's loss; he completed 8 of 16 for 83 yards and ran for a touchdown after replacing Hasselbeck in a 34-18 loss to Atlanta the previous week.
Whitehurst, acquired in an offseason trade with San Diego, was a Chargers' backup from 2006 to 2009, seeing action in just two games and never throwing a pass. He has completed 35 of 63 passes (55.2 percent) for 315 yards, with a touchdown, three interceptions and a 54.7 passer rating for Seattle this season.
Hasselbeck has completed 266 of 444 passes (59.9 percent) for 3,001 yards, with 12 touchdowns, 17 interceptions and a 73.2 passer rating.
Offensive tackle Russell Okung also aggravated a left ankle injury Sunday, but did not miss a play. Carroll did not indicate whether Okung will miss any time. Wide receiver Brandon Stokley also suffered a concussion, but the Seahawks won't know about his availability until later in the week.
The Associated Press contributed to this report.