Only a few can get by without a consistent, bruising and chain-moving running game. In this pass-heavy league, your quarterback must be able to handle all of the responsibilities at the line of scrimmage, including checking into and out of good and bad plays, and then make the necessary throws to keep drives moving. Only a few can reliably do that.

Andy Dalton is not one of the few. That’s why the Bengals’ lack of rushing production over the last few weeks, even the entire year, is a bit troubling going into this weekend’s bout with the Chargers. In combination, BenJarvus Green-Ellis and Giovani Bernard averaged 3.75 yards per carry during the season, well below the accepted average. They’ve picked up yards in chunks at times, however, especially Bernard, and they’ll have to rely on that once again.

To do so, the Bengals will have to block Eric Weddle. The All-Pro Chargers safety was, at times, a pain in the backfield when the two teams squared off in Week 13. He amassed seven tackles and one tackle-for-loss that game, showing his run prowess by shaking off blocks and timely blitzing into the backfield.

His most impressive tackle was the noted tackle-f0r-loss. It came with less than a minute left in the second quarter, with the two teams tied at seven and the Bengals backed up into their own territory. It was 1st-and-10 at the 16-yard line with 52 seconds on the game clock.

The backfield was filled with tight ends and Bernard. Three tight ends to be exact, two in-line and one at the wing alignment. Originally on the right end, the latter shifted to the far left, outside the outside linebacker and slightly inside Weddle. Weddle was the eighth man of a nine-man “soft” box. He was the strong safety on this play, and living up to his title, he lined up at the strength of the offense’s formation.

Predictably, the play-call was a stretch run. Five yards deep into the backfield, Bernard received the handoff from Dalton and stretched the defense horizontally and outside the left hash. Immediate pressure from the defensive line prevented a slicing cutback to the formation’s right, forcing Bernard to keep running wide.

The wider Bernard was, the closer he was to Weddle. Weddle defended smartly by keeping his feet moving while mirroring the tight end that blocked him. He stayed wide, extending his arms out and keeping his pads low to “set the edge” and force Bernard, who he watched throughout the play and anticipated he’d come outside, back into the meat of the defense.

After a few jabs and cuts, Bernard found himself near the B-gap in between the left guard and tackle near the 15-yard line. The interior of the offensive line was a mess, as they failed to prevent penetration and establish an alley for him to run through. Without choice, he was forced to the outside, where Weddle, who let go and ripped the tight end down to the ground,  grabbed him and rode him to the sideline for no-gain.

A quarter later, Weddle was after Bernard again. The clock ticked down to less than 13 minutes left, and with the score still stuck at seven, the Bengals had the ball with 1st-and-10. This time, they had more breathing room with the ball propped on the 46-yard line. But if they were going to make any use of the field position, they had to account for Weddle, who was surely inclined to defend the run.

He was the eighth man in the box box.  He was once again outside the defensive end to his side, which was considered the weak-side of the Bengals’ 11 personnel (one back, one tight end). The Y tight end was lined up to the formation’s right.

As Dalton was about to catch the snap and turn to his right to hand the ball off, Weddle hurriedly came forward, propelling himself off his left foot and into the Bengals’ backfield. Bernard, meanwhile, received the handoff straight down the middle of the formation, and within a couple of steps, sunk his hips and stabbed his right foot into the ground, hoping to make a cut across the formation.

There was no chance. Weddle, unblocked, was there in an instant. His timely intrusion into the backfield made it difficult for the blockers to see him, let alone get a hand on him. He wrapped his arms around Bernard’s midsection and tackled him, sandwiching the rookie runner between the turf and himself.

Although these failed runs were only two of 34 carries for the two running backs, they could foreshadow this weekend’s struggles if the Bengals’ blockers don’t account for Weddle. The free safety will be a force in run defense as long as the Bengals allow him. If they let him run into the backfield, they’ll leave the ball in Dalton’s hands.

And he’s not one to rely on.