Steve Smith's partially torn pectoral muscle, incurred Thursday in practice, will keep him sidelined the next few weeks.
Coach Tom Coughlin would not put a timetable on his top possession receiver's return, saying only that he is now on a "week-to-week" basis.
"They say a limited amount of time, but not necessarily right away or this week or next week," Coughlin said. "I won't know until (Smith) starts rehabbing. He hasn't had much swelling or discomfort, so a lot of it in the beginning will probably be preventative to make sure there's no further injury, and then to strengthen and go forward."
Thus will end his streak of at least one catch in the last 41 games. Taking his place at the "X" spot will be Mario Manningham, who ironically holds the team's top spot on yards per catch at 15.4. Nicks will stay at the "Y", where he has become one of the most athletic and shiftiest of receivers in the open field.
Second-year receiver Ramses Barden will undoubtedly see time as a third wide receiver.
Coughlin said Smith should not have to undergo surgery.
"It's a partial pec and he just has to rehab," Coughlin said. "But whatever the basis of it is, he has to go through a process of healing, so I'm not sure exactly how long."
Meanwhile, moving Manningham into Smith's spot could lead to more double-coverage for Nicks. Other than that, Nicks said the Giants' offense should go on in normal fashion with Manningham out there instead of Smith.
"We know he's going to step up," Nicks said of the Giants' third receiver, who has refined his route running after some severe problems negotiating the sideline last season. "We pretty much all know each other's routes, so it shouldn't be a problem."
Manningham, third on the team with 25 catches for 385 yards and three touchdowns, said he looked forward to an increased role.
"I'll be cool," Manningham said. "I just got to play football; stick to what I do and don't try to make the game harder than it is. The good thing is, we know Dallas and we know what they're going to run."
They should also know that Dallas has basically quit on defense, having given up 121 points over the last three games. Cornerback Mike Jenkins has drawn specific criticism for not going full-out on his tackling. It's unlikely new defensive coordinator Paul Pasqualoni will be able to turn that around in a week.