The past month has seen fixtures along starting offensive lines abruptly leave the picture. Evan Mathis’ release is the latest to beg for a metric that gauges a team’s offensive line continuity compared to other seasons and across the 2015 NFL landscape. Continuity in the trenches has been a long-established indicator for success in the run game. Run Continuity Projection (RCP) describes this relative to other teams by framing it in simple quantified terms — another factor in projecting run output based on opportunity in the coming season. This metric is meant to help flag running backs who will likely need to work much harder for their yards and also identify backfields where a workhorse should have the right surrounding gears to contend for the rushing title, in addition to personnel and coaching. Think LeSean McCoy in 2013 or DeMarco Murray in 2014. Neither occupied the first tier of rushing title favorites — could hit them at odds of 20-to-1 and lower — behind bigger names with less stability up front. Trace back 10 years of rushing titles and find offensive lines that entered the season with relative continuity from the previous year. Nine of the past 10 rushing champs ran behind an offensive line that returned at least four starters. The 2013 Eagles and 2014 Cowboys each would have scored a 4.5 Run Continuity Projection (RCP), as each returning offensive line starter is worth one point and returning 250-plus cumulative TE run-block snaps from the previous year adds 0.5. Now let’s frame this among around the top 10 rushers from each of the past three seasons. As a reference point for RCP, the bottom 10 run-block teams by PFF rankings are aligned with RCP scores. The metric correlates with intuitive sense: the top 10 rushers usually run behind lines returning at least four offensive line starters and the 10 worst run-blocking lines usually return fewer. As with most offseason projections, injuries can hamper and even lay waste to our best dreams of autumn. RCP provides a data point for discussing continuity in front of running backs, which has shown to factor significantly in performance and production. More to come in future articles. Thoughts, critiques and suggestions are all welcome @ThomasEmerick. Source.