LAKE FOREST – In the years that have passed since he was trying to deal with C.J. Spiller's speed in college, Willie Young still hasn't forgotten.
Young, in his first year on the Bears' new-look defensive line, watches the way Spiller runs on film. As was the case when Young was at North Carolina State and Spiller was at Clemson, Young understands how difficult it is to pigeon hole the Buffalo Bills' leading rusher into one simple category.
Like the rest of his Bears teammates', Young knows how explosive and elusive Spiller can be once he gets around the corner. But just the second that a defense thinks it has has the AFC's reigning fifth-leading rusher figured out and Spiller will burst through an opening in the offensive line and disappear down the field.
"You can't predict where he's going to go," Young said Wednesday. "You have to treat him like you're playing Adrian Peterson, you've got to treat them like you're playing Marshawn Lynch – it's just a different kind of cats they've got over there (in Buffalo)."
As if stopping Spiller wasn't enough, the Bears on Sunday must also deal with Spiller's backfield mate, Fred Jackson, who finished directly behind his teammate on the AFC's rushing leader list in 2013. How equal are they? Spiller finished last season with 933 yards on 202 carries while Jackson tallied 890 yards on 206 rushing attempts.
Throw mobile Bills quarterback EJ Manuel into the mix and the Bears – who ranked 32nd in the NFL against the run last season – know exactly what kind of challenge they'll face in Sunday's season-opener at Soldier Field.
"Guys like Spiller and Jackson, they're just so quick to be able to – when you get out of your gap one second – they can jump, stop, cut, and be right back in your gap full-speed in no time," Bears defensive end Jared Allen said on Wednesday. "It's just going to be disciplined football. We've got to tackle.
"That's going to be the biggest thing this week is tackle, tackle, tackle."
As as simple as gap assignment football may seem, Bears rookie defensive lineman Ego Ferguson begs to differ. As Ferguson what stands out about the Spiller-Jackson combination and he answers quickly.
"Speed," Ferguson said Wednesday. "All of them (Spiller, Jackson and Manuel) have speed. All of them can can take it the distance. So the biggest thing for us is to be disciplined and stay in our gaps.
"But that's easier said than done when you've got 320-plus (pound) guys in front of you trying to get you out of your gap. So imagine how hard that is."
As much as the Bears struggled to shut down the run last season, safety Ryan Mundy prefers to not focus on 2013's narrative, but on the improvement he and his teammates believe has been made in the offseason when the Bears added Allen, Young and Lamarr Houston to a defensive front decimated by injury last season.
But just how much better the Bears can be against the run this year will be put to the test Sunday when Spiller and Jackson put the Bears through their paces. The Bills ranked second in the NFL last season with 144.2 rushing yards a game, making it clear what the Bears' defensive mission must be.
"Our first and foremost goal is to stop the run," Mundy said.
Defensive coordinator Mel Tucker characterized the pair as hard-charging, physical backs who know how to run the football. He referred to Sunday's opener as a "huge test", acknowledging like everyone else around Halas Hall Wednesday of just how big of a challenge the Bears will face.
The difference, Young said, will come down to who is able to dictate what they want to do over the course of Sunday afternoon.
"Those guys are trying to make a statement and we're trying to make a statement," Young said. "No doubt it brings out the best in you. But we're fresh and we've had a couple of weeks to get ready for one another and so it's going to be very exciting. It's going to be high intensity, a lot of trash talking, a lot of physical play going on."