Seattle Seahawks quarterback Tarvaris Jackson has a high-grade strained pectoral muscle in his right chest and will be rested during the team's bye week.
Seahawks coach Pete Carroll said Monday that Jackson had an MRI exam that "showed some stuff" in the pectoral area, but there is no time frame for how long the quarterback might be out.
Jackson was injured during the third quarter of Sunday's 36-25 victory over the New York Giants and was replaced by Charlie Whitehurst.
"He felt better today than he did yesterday, but we won't know," Carroll said of Jackson. "We're not going to know for a while. We won't have him throw the football for a little bit and see what happens, but it is on his throwing shoulder."
Jackson was hurt during the third quarter on a designed quarterback run that went for 11 yards. Three Giants players landed on him at the end of the play.
"I thought that Tarvaris did well throughout with a couple of throws that he tried to jam in there, and I'm still mad at him for running and getting hit when he could have got down," Carroll said.
Carroll said Whitehurst, who led the Seahawks to three scoring drives during the fourth quarter and finished 11-of-19 passing for 149 yards and one touchdown, would take over as the starter in the interim.
"We got a really good performance from Charlie yesterday," Carroll said. "He did the things we needed to do to keep the game moving and then had enough there to finish it off and get the touchdown drive that we needed to win the football game, so we're really pleased about that."
Carroll was asked Monday if there was a quarterback controversy brewing after the way Whitehurst played.
"There is no controversy brewing here in this building," Carroll said. "You guys can have all the one you want."
Jackson leads a list of significant Seahawks injuries that includes Pro Bowl tight end Zach Miller (neck), running back Marshawn Lynch (ankle), cornerback Marcus Trufant (back) and linebacker Leroy Hill (hamstring).
Carroll said Lynch would sit out practice this week, adding, "He's hobbling." The coach also said Miller's status was yet to be determined after an MRI exam Monday, and he described Hill's hamstring injury as "mild."
Seattle won in New York without starting wide receiver Mike Williams (concussion) and cornerback Marcus Trufant (back), who were inactive. Carroll said Trufant's back was so problematic Sunday morning that the cornerback couldn't bend over to tie his shoes.
The Associated Press contributed to this report.