What will they do now if both players are sidelined?
Jackson's status is uncertain after the dynamic wide receiver sustained a concussion in Sunday's 27-24 win over Washington. Meanwhile, Westbrook will be re-examined this week after missing the last two games with his second concussion of the season.
Jackson was injured on a hit after running a short crossing pattern in the third quarter. He didn't lose consciousness and left the field on his own.
"He doesn't feel bad today," coach Andy Reid said Monday. "We are as cautious as they come with concussions. We're going to continue to test him and go through the process."
Rookie running back LeSean McCoy and veteran fullback Leonard Weaver have filled Westbrook's absence in the backfield. Jackson has replaced him as the offense's big-play threat.
Jackson has 44 catches for 769 yards and six touchdowns. He's also scored on a run and a punt return. All of his TDs are 35 yards or longer, including six beyond 50 yards.
"If guys go down, the next guy better go in and do his job," Reid said. "That's what our guys do here."
Without Jackson, Donovan McNabb relied on Jason Avant and rookie Jeremy Maclin to make big catches against Washington in the fourth quarter of the team's second straight comeback win.
"We have some guys that can make plays for us and you just want to give them opportunities to do that," McNabb said. "Obviously, (Jackson) is a big-time talent and a guy that has just kind of came into his own this year. We just want to spread it around and give guys opportunities to make plays for us."
The diminutive Jackson -- he's generously listed at 5-foot-10, 175 pounds -- is vulnerable in traffic because of his size.
"He has a lot of success in there with the underneath crossing routes," Reid said. "This one here he got caught on. He got hit; really that hit was more on the shoulder. It wasn't really on the head as it was really on the shoulder there."
The team expects Westbrook to see specialists this week in Pittsburgh. The doctors said they wanted to see Westbrook two to three weeks after their previous exam Nov. 18.
"I'm not sure exactly what step the doctor will take with him," Reid said. "I don't know that. We'll see what phase the doctor feels he's at and the doctor will determine what he will do. If that's going back on the field, we'll do that. If that's more conditioning work in the weight room, we'll do that."
Westbrook experienced a mild headache last week after a workout. The 30-year-old former All-Pro sustained his first career concussion when he hit his head on a defender's knee during a Monday night win at Washington on Oct. 26. He briefly lost consciousness but walked off the field under his own power.
Westbrook returned against San Diego on Nov. 15 after missing two games. But he sustained another concussion when he got sandwiched between a blocker and a tackler on a screen play.
"I know a lot is being said about concussions," Reid said. "We are as conscious as they come with concussions. We are going to do everything within our power to get (Jackson) the proper treatment and diagnosis. To compare to Brian's, are we going to be more cautious? No. We're always cautious. We're going to do what we do."
Copyright 2009 by The Associated Press