Dominate at the line of scrimmage and win football games. This is a basic football truth. Yet, despite the immense importance of the battle in the trenches, this area of football often gets overlooked by the fantasy playing public. That’s not to say that they’re completely oblivious to line play, but the common perspective among many attributes rushing productivity solely to the running back.

There’s no doubt that running backs are responsible for a good portion of their rushing totals, but even the league’s best backs need a little help from their offensive lines. Running backs who are given more space to operate tend to produce more rushing yards and vice versa.

An easy way to quantify the amount of space an offensive line creates in the run game is with yards before contact. Likewise, yards after contact gives us an indication of a running back’s performance independent of his blocking.

So which offensive lines produced the most space for their running backs? Here’s a look at the yards before contact per running back rushing attempt in 2017:

Yards Before Contact Per Attempt Tm AVG Left Middle Right CAR 1.91 2.42 1.36 1.79 LA 1.89 1.31 3.02 1.45 JAX 1.89 2.41 1.27 1.82 NO 1.88 2.18 1.92 1.62 GB 1.83 1.61 1.55 2.39 BUF 1.80 2.23 1.65 1.52 NE 1.76 1.76 1.79 1.71 SF 1.73 3.07 1.36 0.89 CHI 1.70 2.07 1.49 1.36 BLT 1.66 1.97 1.84 1.37 TEN 1.66 2.72 0.91 1.07 KC 1.65 1.35 2.66 1.17 DAL 1.59 2.52 1.24 1.22 CLV 1.52 2.15 1.62 0.77 HST 1.50 1.33 1.65 1.47 NYJ 1.49 1.38 1.69 1.37 PIT 1.46 1.92 0.98 1.52 ATL 1.44 1.35 1.33 1.64 NYG 1.44 1.08 1.77 1.34 MIN 1.43 0.81 1.17 2.14 OAK 1.42 1.52 0.99 1.76 LAC 1.37 0.95 1.26 1.87 CIN 1.31 1.19 1.28 1.41 DEN 1.29 1.03 1.69 1.13 PHI 1.24 1.63 0.91 1.07 WAS 1.23 1.23 1.90 0.63 TB 1.18 1.04 1.53 1.00 SEA 1.15 1.33 0.81 1.27 ARZ 1.14 1.12 1.03 1.24 IND 1.02 0.82 0.82 1.45 DET 0.81 1.46 0.53 0.32 MIA 0.59 0.16 0.91 0.63

On average, offensive lines produced 1.47 yards before contact for running backs during the 2017 regular season. That number is down nearly 10 percent from the 1.63 yards before contact produced in 2016 and is the lowest since PFF started collecting data in 2007.

Likewise, this is the first year in the PFF era where no offensive lines averaged over 2.00 yards before contact per attempt. Six teams topped that mark in the 2016 season with the Bills leading the way with a massive 2.88 yards before contact, which was the top number in the PFF era.

The Panthers paced the league this year with 1.91 yards before contact per attempt. This likely comes as a surprise, considering the fact that Christian McCaffrey and Jonathan Stewart both averaged under 4.0 yards per carry. Of course, neither player was effective after contact. Stewart averaged 2.23 yards after contact per attempt, which ranked 45th out of 53 qualifiers with at least 25 percent of team carries. McCaffrey was even worse, finishing 50th with 2.11 yards after contact per attempt. McCaffrey is an exciting player, but he’ll need to improve on that number in order to be a more effective fantasy option.

Unlike the Panthers, it shouldn’t come as any surprise that the Rams were among the league’s top units in this stat. This was a dramatic improvement from 2016 where Los Angeles created the fifth-fewest yards before contact at just 1.11 yards. Not so coincidentally, Todd Gurley went from being widely regarded as a fantasy bust to the league’s top fantasy running back. With the Rams trending in the right direction, Gurley is locked in as an elite option.

Jacksonville entered 2017 with a commitment to the run and they stuck to their game plan. Leonard Fournette was one of just nine running backs to top 1,000 rushing yards, and he got a lot of help from his offensive line. Likewise, the New Orleans duo of Mark Ingram and Alvin Kamara benefited from the space their offensive line produced. Unlike McCaffrey and Stewart, the Saints backs also created yards on their own. Kamara ranked second in yards after contact (3.83) and Ingram finished tied for eighth (3.09).

There are also a few surprises in the top 10. Green Bay struggled with injuries at the running back position this past season, but their offensive line created a lot of space. The back who wins the starting job in 2018 could be a sneaky value in drafts. There wasn’t much to get excited about from Kyle Shanahan’s first year in San Francisco, but his offensive line did manage to generate a lot of space for the backs. Carlos Hyde could be on his way out, but there will be fantasy appeal for whoever ends up as the 49ers lead back.

On the other end of the spectrum, we see the Seattle offensive line continue to struggle. Seahawks backs had little space to operate with just 1.15 yards before contact. Of course, it wasn’t just the line play that made the Seahawks backfield a mess for fantasy purposes this year. Injuries ravaged the backfield, causing Seattle to use six running backs during the season. Of that bunch, just one played more than 25 percent of the offensive snaps: J.D. McKissic with 297 snaps. While Chris Carson and Mike Davis flashed upside during the season, it’s going to be tough to trust a Seahawks back in fantasy next season unless the team upgrades its offensive line.

The Cardinals dealt with injuries along the offensive line this season, but we certainly want to see their number go up for David Johnson’s sake in 2018. Indianapolis with have a new regime in place, but whoever takes over will have their work cut out for them. Likewise, Detroit has a lot of work to do along the offensive line. This is the second straight year the Lions have finished 31st in this stat category. Without major upgrades along the offensive line, it’s going to be tough to trust any Lions back for fantasy purposes.

Miami not only finished with the lowest yards-before-contact number in 2017, but the Dolphins also managed to post the lowest number in the PFF era. The offensive line generated essentially no space for their running backs, which makes Kenyan Drake’s performance down the stretch that much more impressive. Drake finished the season with the league’s highest yards after contact per attempt with a massive 4.29 yards. In fact, that’s the highest total in the PFF era, and Drake is the only back to top 4.00 yards after contact per attempt with at least 25 percent of his team’s carries. Drake is likely to open the year as the Dolphins’ lead back, and he’s one of the best bets to break out at the running back position in 2018.

In looking back at running back production from 2017, offensive line certainly played a role in fantasy production and should be considered when you construct your fantasy draft boards. Of course, the offensive side of the ball only tells part of the story. We also need to consider how much space defensive fronts allowed to their opponents. We’ll take a look at those stats in our next piece.