The Difference is Escapeability: Comparing Vanderbilt's Current Running Backs to Zac Stacy

After decades of waiting, Vanderbilt finally has a gold standard when it comes to running the ball. Zac Stacy emerged from a underclassman platoon to become the school's leading all-time rusher and the catalyst behind a pair of bowl bids. His presence ushered in a new era of Commodore offense by moving the chains on the ground and opening up passing lanes for Jordan Rodgers behind him. In simple terms, Stacy was the best tailback Vandy has had in the modern era.

Replacing him has been difficult. The 'Dores have three talented playmakers splitting time in the backfield, but the sum of their parts has yet to equal the performance of their predecessor. Jerron Seymour, Brian Kimbrow, and Wesley Tate have all shown flashes of ability, but they haven't provided the stable rushing presence that the team needs to keep drives alive and bring consistency to the Commodore offense.

Seymour has been the closest. The redshirt sophomore is second on the team in total carries but he also has Vanderbilt's most rushing yards (351) and best yards-per-carry average (5.9). Tate has settled in as a change-of-pace bruiser who can lead the team from the wildcat formation. And Kimbrow, when he's not in the doghouse, is Vandy's fastest option. He's also shown growth in terms of picking up blitzes and contributing to this team away from the ball.

Still, it's clear that James Franklin misses his now-graduated workhorse running back.

A big part of the gap in the running game between 2012 and 2013 is Stacy's ability to break free and move the chains to sustain the Vanderbilt offense. I went back and broke down every rushing attempt that Stacy had as a junior and senior and matched those carries up against the 'Dores current running back platoon. The data I was looking for was a player's ability to get past the linebackers and through the secondary - a skill that requires a combination of speed, strength, and elusiveness. In order to gauge this, I totaled up each player's carries and the number of runs that went for 12 yards or more.

These data point out exactly what was so special about Stacy. When he got the ball, there was an approximate one in eight chance that he was going to take it 12 yards or more. While he wasn't the biggest or fastest runner in the stable, he had the vision and ability to create space and charge forward.

It also points out something many fans already knew - that Kimbrow, over the past two years represents this team's biggest home run threat. For his career, the sophomore speedster is operating at a higher level than Stacy did as a senior. However, it's also important to note that many of his biggest runs came against inferior opponents. Breakout games against Presbyterian, UMass, and Kentucky may be skewing his numbers.

Seymour falls significantly far behind Kimbrow using this metric, but much of that can be attributed to a freshman season that started strong but ground down to a slow march as the year wore on. He's been much better in 2013, where he's broken seven runs for 12 yards or more in 59 carries. That would put his breakout rate at 11.86% - better than everyone but Stacy's 2011 campaign.

Tate, as expected, rates out as more of a power back than a breakaway runner. Observations would suggest that he's more likely to break a long run out of the wildcat than as a traditional tailback, but I can't back that up with statistics right now.

The numbers suggest that Seymour and Kimbrow have the best chance at replicating Stacy's performance for the Commodores, but they don't take intangibles like Tate's leadership into account. If Seymour can keep his 2013 momentum going and Kimbrow can apply the skills that led him to big runs against low-level opponents to SEC games, then the 'Dores can successfully replicate what Stacy brought to the table - and more. However, the first step will be carrying a consistently high level of play from week to week before the Vandy rushing offense can truly be dangerous. This team needs that more than a home run threat halfway through their season.