NEW YORK -- The Giants didn't escape Seattle completely unscathed.
According to a person with knowledge of the diagnosis, starting left tackle David Diehl injured a muscle in his hip and hamstring during the Giants' 41-7 win over the Seahawks on Sunday. Diehl is considered week-to-week depending on how he responds to treatment, according to the person with knowledge of the injuries.
Diehl told ESPN 1050's Brandon Tierney that he has a partial hamstring tear that may sideline him for several weeks. The Giants said only that Diehl has a hip injury that was being evaluated on Monday afternoon.
"At first, I thought it was an ankle or a knee -- he kind of bowled over backwards," Giants coach Tom Coughlin, describing Diehl's hip injury, said Monday on a conference call. "It's in the isolated areas up in the hip area. Exactly what it is, I'm not sure. We're waiting to find out."
Diehl injured his hip blocking on an extra point in the second quarter.
In addition to the Diehl injury, Coughlin said that backup offensive lineman Adam Koets will be out for the season with a torn left ACL. Koets started in place of O'Hara for three games earlier this season when the center nursed an injury to his left ankle and Achillies.
O'Hara sat out on on Sunday against the Seahawks with a mild right Lisfranc sprain. Coughlin started left guard Rich Seubert at center against Seattle. Coughlin said Monday that he had no update on O'Hara, who may miss another week.
Koets, one of the Giants most versatile lineman, injured his ACL on a non-contact play in which his cleat appeared to get caught in the Qwest Field turf. An MRI taken Monday revealed the extent of the injury.
"Very disappointed in the loss of Adam Koets," Coughlin said. "He was running to the right sideline, right in front of our bench really, then all of a sudden went down. It looked like he caught his cleat and just twisted the wrong way."
The Giants appear to have contingency plans for the Diehl and Koets injuries.
Seubert is probably Coughlin's best option at center for Sunday's game against Dallas. Coughlin also said on Monday that injured lineman Kevin Boothe will be activated this week and has some experience at center. Boothe was on the physically-unable-to-perform list with a torn pectoral muscle but has recently been practicing with the team. Coughlin said that both Boothe and Chris Snee have taken snaps at center.
Replacing Diehl, who played tackle but was versatile enough to take snaps at left guard, will be difficult. The veteran has started 127 straight games (including the playoffs) for the Giants.
Shawn Andrews played left tackle against the Seahawks and could remain at tackle against Dallas with Boothe sliding to guard and Seubert under center. Rookie Mitch Petrus may also see playing time at guard.
"Shawn played well at left tackle," Coughlin said of Andrews. "He was energetic and enthusiastic about playing."
On Sunday, Diehl played left guard and Seubert moved to center. Andrews, who was a Pro-Bowl guard in Philadelphia, made his first NFL start at left tackle. Koets was an extra offensive lineman used as an eligible receiver at tight end on a few plays.
Coughlin was looking for a veteran offensive line to handle the noise at Qwest Field and it worked well as the linemen helped the Giants gain 487 yards and score touchdowns on five straight possessions in the first half.
Now, Coughlin and his coaching staff will be forced to shuffle the line again before this Sunday's home game against the reeling Cowboys, who on Monday announced that offensive coordinator Jason Garrett will replace the fired Wade Phillips.
"I thought that the group played well together," Coughlin said of his offensive line's effort against the Seahawks. "Certainly these things are pretty much week to week, depending on who's available and who isn't but I certainly like the way our group [on Sunday] played."
Coughlin also said that receiver Hakeem Nicks suffered a lateral ankle sprain but was feeling good on Monday.
Ian Begley is a regular contributor to ESPNNewYork.com. ESPNNewYork.com's Ohm Youngmisuk contributed to this report.