Forget the pass ... what about Dion Lewis?

In the great chess match that will take place Sunday at Heinz Field, Keith Butler will match wits against Tom Brady. It's not exactly Donald Byrne against Bobby Fischer, but it's important nonetheless.

The problem is, Butler will be doing so without his most important piece, Ryan Shazier, the one player capable of making plays at all levels of the field. Shazier, who suffered a season-ending back injury two weeks ago in Cincinnati, was placed on injured reserve earlier this week. There was, however, some good news regarding his status Thursday.

Without their star inside linebacker the past two weeks -- Shazier was injured early in the first quarter -- the Steelers have struggled defensively, allowing 353 total yards against the Bengals and 413 to the Ravens last week. They have won both games and take an eight-game winning streak into Sunday's game at Heinz Field against New England (10-3). But to beat the Patriots, the Steelers know they need to be better defensively -- especially against the run.

Wait, isn't Brady, the five-time Super Bowl-winning quarterback, supposed to be the issue?

"You can’t do what we’ve done in the last two weeks," said Butler. "We have to play better against the run than we have in the last two weeks. We have to make sure we take away Dion Lewis. He’s a good runner for them, and we have to do a good job in the running game and when they go play-action and when they throw the ball. We have to try to hang in there with them."

And if they can slow the Patriots' running game, they can then get after Brady, something that could be necessary to win.

They feel they have a plan to make that happen.

"We just came up with some stuff right now to see that we stop that," Stephon Tuitt told me Thursday. "We can’t be giving up all that rushing to teams. That’s not us. That’s not the Steelers' way. After what’s happened the past two games, if I’m the other side, I’m like, ‘Yeah, we’re going to run the ball.’ We gave up 100 yards. But we came up with some stuff to stop that. You have my word, you’re going to see something different."

Different would be good. After allowing more than 200 yards rushing to Chicago and Jacksonville early in the season, the Steelers hadn't given up more than 100 yards in a game until giving up 130 on the ground to Cincinnati and 153 to Baltimore. The Steelers still rank ninth in the league, allowing 102.9 rushing yards per game, but are 2-2 in games in which they allow the opposing team to top 100 yards on the ground. They have recorded 41 sacks this season, but just three in the past two games because they have to respect the run so much.

The Patriots are 15th in the NFL running the ball, averaging 113.2 yards per game, and they utilize their running backs in many different ways. Lewis, a former Pitt star, leads the team with 607 yards on just 117 carries, an average of 5.2 per attempt. Mike Gillislee is a bigger back and hasn't been active in recent weeks but still has produced 355 yards and four scores while Rex Burkhead, formerly of the Bengals, has 252 yards and four touchdowns on just 60 attempts.

All, with the exception of Gillislee, are also accomplished receivers out of the backfield. James White, who has 171 yards rushing, is tied for second on the team with 54 receptions for 421 yards and three touchdowns, while Burkhead has 29 catches and Lewis 20.

There might not be a player as dynamic as the Steelers' Le'Veon Bell, who leads the NFL in rushing and is ninth in the league with 75 catches, but they are effective as a group.

"We’ve got a big challenge in trying to stop these backs and trying to get after their quarterback," Javon Hargrave told me.

Especially without Shazier, easily the Steelers' fastest linebacker, who can make plays like this:

Last week against Baltimore, with Tyler Matakevich, their top backup inside linebacker, out with a shoulder injury, the Steelers went with a rotation of Sean Spence, Arthur Moats and L.J. Fort to replace Shazier.

Spence, signed as a free agent following Shazier's injury, played 34 snaps despite having been out of the league since being released by Indianapolis in early October. Moats, an outside linebacker by trade, played 19 snaps, while Fort, who has spent time on and off the Steelers' practice squad the last few seasons and was even released earlier this year, got eight.

All of Fort's action came when the Steelers were in their dime defense. Because of how the Patriots often align themselves offensively, with three receivers on the field, the Steelers could use a lot of their nickel and dime packages this week.

Fort, who also spent some time early in his career on the Patriots' roster, knows whichever linebacker is out there in place of Shazier is going to have a target on his back.

"Oh yeah," Fort told me. "You watch film and you see that’s been an area of weakness. They do a great job of studying and preparing for their opponents, so I’m sure that’s one area they will attack."

To countert that, the Steelers might shorten the leash a little on exactly who is out there with Matakevich still limited in practice this week because of a shoulder injury. Instead of a three-man rotation, for example, we could see just two, with Spence playing in the base defense and getting some work in the nickel and Fort playing on obvious passing downs.

Last week against the Ravens, they went with a defense that included Hargrave staying on the field with Tuitt and Cam Heyward, outside linebackers T.J. Watt and Bud Dupree and six defensive backs.

At one point, Hargrave even dropped into coverage, allowing a short completion to running back Danny Woodhead to go for a 22-yard gain.

"I've got to work on my coverage skills," Hargrave joked.

They went with Watt on the field at the same time as James Harrison, who replaced Dupree for what turned out to be the final play of the game against the Ravens.

All joking aside, the Steelers are trying to figure out a way to get their best 11 defensive players on the field at the same time.

But Butler knows he has to guard his secrets closely. He's not tipping his hand about how the Steelers plan to shore up their rushing defense.

"I think we have a plan that we have to try to use and we’re going to put our best guys out there if we can," Butler said. "I think (Mike Tomlin) addressed that. I don’t think can add much to what he has already said about it. We have a plan that we are going to try to use and get these guys playing. And we need play better than we did last week, obviously."

Or, as Hargrave put it, "When a team can run the ball on you, they can do anything. That’s why we’ve really got to stop the run this week so we can get ourselves in pass-rush situations."

MATT SUNDAY GALLERY