The Arizona Cardinals are in a position to keep four running backs on their 53-man active roster during the 2016 season, and the team has an intense competition brewing for its final spot.
Behind starter David Johnson and backups Chris Johnson and Andre Ellington, a pair of fourth-year reserves in Stepfan Taylor and Kerwynn Williams are vying to become the Cardinals' fourth running back.
In most cases, a team's decision to keep one player ahead of another at a position is more complicated than how each player fits a particular position. Salary cap considerations, injury history, and position groups needs play large roles in roster battles, and the competition for Arizona's fourth running back spot is no different.
Fortunately for the Cardinals, the 2016 salaries of Taylor and Williams are separated by just $125,000, which is a small enough difference in NFL terms that Arizona can afford to use other means for evaluating the duo.
Fortunately for each player, neither Taylor or Williams has a significant injury history, as Taylor has played in at least 14 games in all three of his professional seasons while Williams has bounced between the Cardinals' active roster and practice squad over the past two years and served as an insurance policy for situations when other running backs have been hurt.
Barring an injury to either player over the final two and a half weeks leading up to the season opener, Arizona is in a strong position to allow its roster needs to dictate whether Taylor or Williams makes the roster.
With a bell cow running back in David Johnson in line for a larger role, the Cardinals already have two established backups in Chris Johnson and Ellington who can carry the football and ease the load on the team's starter. With that in mind, running the ball, seemingly the primary job of a running back, is actually among the least distinguishing skill a fourth running back needs to possess.
The Cardinals need their fourth running back to be able to catch passes, pass block, and most importantly, play special teams, and it's Taylor who edges out Williams in each of those categories. While we consider Williams the better pure running back of the pair, his skill set is somewhat redundant to Ellington's which makes him more expendable.
Williams could offer the Cardinals a change of pace option who has the speed to get to the edge and the shiftiness to make defenders miss late in a drive, but Ellington does each of those things better than Williams, and Ellington is still just the third player on Arizona's depth chart.
The Cardinals would be better suited to keep Taylor, who might be the team's best pass blocking option, because of the options he brings the team in obvious long yardage and short yardage situations.
At 5-foot-9 and 214 pounds, Taylor is also the closest player Arizona has to a true fullback, and because the Cardinals won't keep a fullback on their roster, Taylor gives the team the flexibility to put him on the field and use him in that capacity in short yardage situations.
While Williams is the best pure rushing option Arizona has competing for the coveted fourth running back spot, Taylor is a superior full service option who can play fullback in short yardage sets, pass block in third and long situations, serve on the punt protection unit, and help Arizona's kickoff return team.
Because of roster limitations in the NFL, position battles become more complex than simply choosing a player because of a more dominant skill. A broader array of skills can keep a player in the league for many years, and in Taylor's case, his skill set should keep him on the Cardinals' roster this season.