Weaver and Jackson were among several Eagles injured in Sunday's 27-20 loss to the Green Bay Packers. Starting quarterback Kevin Kolb and linebacker Stewart Bradley also missed some of the game because of concussions.
Reid said Weaver, a Pro Bowl selection last season, will have surgery to repair what he termed a "severe" anterior cruciate ligament tear in his left knee. Jackson is to undergo surgery this week for a torn triceps muscle.
Kolb and Bradley, under NFL standards regarding head injuries, may be left home next week when the Eagles play at Detroit. They are to be evaluated in three- and five-day increments until cleared to play.
"You have to go through this protocol. I can't tell you (they won't play Sunday)," Reid said. "They have to go through this whole evaluation process before they can be cleared. I don't want to do anything that puts these guys at risk."