"I saw a lot of chaos out there," Marshall said. "I thought: 'Man, I wouldn't want to play in that offense. It seems like there's so much going on.' I needed to see more, and now, deep in the season, it's legit. They have special guys and have a special system. It's definitely a legit system, but at the beginning, it wasn't for me. It was tough to see. Those guys, it seemed like they were running with their heads cut off. Now they've got it down pat and they're rolling."
Marshall will get a sideline view of Kelly's up-tempo offense on Sunday when the Chicago Bears (8-6) visit Philadelphia (8-6) in a matchup of division leaders. The four-time Pro Bowl receiver will try to help the Bears outscore the high-flying Eagles.
Only Denver has scored more points than Chicago this season, so this could be quite an offensive showdown. Jay Cutler, Matt Forte, Marshall and Alshon Jeffery vs. Nick Foles, LeSean McCoy and DeSean Jackson.
Things could get ugly for a pair of defenses that have struggled.
"Chicago might be one of the most talented offenses we face," Eagles defensive coordinator Billy Davis said. "This is overall our biggest test."
Here are five things to watch for when the Bears visit the Eagles on Sunday:
PLAYOFF IMPLICATIONS: Both teams have a chance to clinch a division title. If the Cowboys lose to Washington, the Eagles win the NFC East and secure the No. 3 seed with a victory. The Bears would win the NFC North and lock up the No. 3 seed with a win and if Green Bay loses to Pittsburgh and Detroit loses to the New York Giants.
There's also a chance the game won't mean anything win or lose for the Eagles except a potential No. 3 or 4 seed. If the Cowboys beat the Redskins, the Eagles must beat Dallas in Week 17 to win the division. A loss to the Bears won't hurt their division hopes, but don't expect Kelly to rest his starters.
If that happens, Eagles guard Evan Mathis joked: "I think we're going to cancel the game and invite the Bears to a movie or something; might go see 'Anchorman 2.'"
BEST VS. WORST: LeSean McCoy, the NFL's leading rusher on the league's top rushing offense, gets a chance to pad his stats against the worst-rated run defense in the league. The Bears are allowing 152.4 yards per game on the ground. McCoy ran for a franchise-record 217 yards in blizzard-like conditions in his last home game vs. the Lions on Dec. 8. He had just 38 yards on eight carries in a loss at Minnesota last week.
"He's certainly special. He's such an explosive player, he can do it all," Bears coach Marc Trestman said. "He's certainly one of the best in the league. He's a difference maker. We're going to have to know where he is and we're going to have to do whatever we can to neutralize him."
MARSHALL & JEFFERY: Chicago's Brandon Marshall and Alshon Jeffery have combined for 170 receptions, 2,450 yards receiving and 17 TDs. They'll be going against a banged-up secondary that's allowed the second-most yards passing and was picked apart by Minnesota's Matt Cassel last week. The Eagles could be missing nickel cornerback Brandon Boykin and backup safeties Kurt Coleman and Colt Anderson because of injuries.
"It doesn't matter who we're playing, we're going to play our football," Marshall said. "So the same routes, and same concepts, same formations, we're going to get to that."
BRIGGS RETURNS: Seven-time Pro Bowl linebacker Lance Briggs is hoping to play for the first time since he sustained a small fracture in his left shoulder on Oct. 20. Losing Briggs has been a major reason the Bears have struggled against the run. They dropped from 12th against the run with him to 32nd.
"It would be huge. I think Lance is definitely one of the best linebackers in the league," Bears defensive lineman Corey Wootton said of getting Briggs back.
PEPPERS VS. PETERS: Bears defensive lineman Julius Peppers going against Eagles left tackle Jason Peters will be a matchup of perennial Pro Bowl players. Peppers has 6½ sacks this season. Peters is having another strong season after missing last year following surgery to repair his Achilles tendon.
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