Still, Diehl optimistically says his goal is to miss just one game and return the following week against Philadelphia on Nov. 21.
"It's my hamstring," Diehl said on his weekly spot on 1050 ESPN's McDonald and Tierney show. "I hurt my hamstring. I am just glad that it isn't my hip because if you hurt your hip then that is surgery and stuff like that. It is muscular and it will take a little time to heal up a little bit. My goal is to be back at Philadelphia next week."
Diehl is considered to be week to week by the team depending on how his body responds to treatment. He initially told 1050's Brandon Tierney that he could be out for several weeks with a slight tear in his hamstring. A person with knowledge of Diehl's diagnosis said that the tackle had muscle injuries to both his hamstring and hip and that one injury wasn't more serious than the other, although Diehl is more concerned about his hamstring.
He is just one of several injured offensive linemen at the moment for the Giants. Starting center Shaun O'Hara is dealing with a mild sprain of the Lisfranc in his right foot and likely could also miss the Dallas game on Sunday. Backup center Adam Koets was placed on the injured reserve list on Tuesday with a torn ACL.
O'Hara said he is pushing to return to the field this weekend but does not know the likelihood of that as he grows frustrated with his injury.
"Yesterday [I] just got some treatment and tomorrow I am going to see how it feels and what we can do," O'Hara told Sirius NFL radio on Tuesday. "Foot sprains, as I am learning, as much as they are painful they are also very slow to heal. I am optimistic, and I am frustrated, that's for sure. I don't know what the prognosis is for this week. Obviously with other guys getting dinged, I am pushing even more to get out there."
Offensive lineman Kevin Boothe was activated off the physically unable to perform list and could see playing time immediately with Diehl's consecutive streak of 127 regular-season and postseason games played ending on Sunday.
The Giants may start Rich Seubert for a second straight game at center. Coach Tom Coughlin started the left guard at center and moved Diehl to left guard and started Shawn Andrews at left tackle against Seattle.
Andrews likely will start a second straight game at tackle with Diehl out.
Diehl said he hurt his hamstring and hip on an extra-point near the end of the first half.
"Got my leg trapped underneath when guys were pushing under me," Diehl said. "I got to do whatever I can to heal up as fast as possible.
"I'm going to try to do my best to make sure I am back," Diehl added. "This is the first time I have been hurt. I have been able to fight through some things before. My goal is to try to come back for that [Eagles] game."
The Giants announced that before Koets was injured Sunday, he and long-snapper Zak DeOssie signed two-year extensions on Saturday.