By Nick Citrone (@pyrollamas)
- Quarterbacks need should be addressed in the first round, teams trying their luck with late round QBs rarely find success.
- Offensive linemen offer superior value in all rounds of the draft.
- Linebackers & running backs are best value on Day 2 (Rounds 2 and 3).
- Teams seeking depth at Defensive Line or Defensive End are better off waiting till Day 3.
- Despite the recent surge in Star Wideouts, WRs offer less relative value than other positions
Free agency is winding down, and the NFL Draft is fast approaching. The next 30 days will feature hundreds of mock drafts, player rankings, film study and roster analysis. Experts and fans alike will hypothesize about how best to fill each teams needs and who should go where. Which QB is best? What are the top needs of each team? Which players are being underrated or overrated? These are important questions that will be debated and written about at length.
One question often overlooked, however, is where in the draft is it best to draft each position? Using historical NFL Draft data and simple statistical methods, we can work to answer this question and gain insight on maximizing draft value.
The idea is simple: identify trends in the NFL Draft by plotting expected value added by position with each pick in the draft. To do this, I constructed a dataset consisting of all 3820 draft picks made between 1999 and 2013, with information on pick number, position, length of NFL career and Pro Football Reference’s Career Approximate Value.
Approximate Value (AV) is PFR founder Doug Drinen’s attempt at creating a single number metric of player performance applicable to every player on the field. It is created by first calculating offensive and defensive team values and then distributing the total among individual players based on the contribution of each. The detailed methodology and reasoning behind the metric can be found here , but all you really need to know is it’s a measure of how much a player has contributed to his team. Approximate Value is not a perfect metric, but this statistical analysis can be easily replicated with other response variables (e.g. Salary per Season, Pro Football Focus’ Player Grades).
Once I gathered my data, I used the ggplot package in R to create smooth splines of the expected AV per season of drafting each position at each point in the draft. The below graphs show these splines for offensive and defensive positions. The thick black line is the overall average from all positions, and the dashed vertical lines indicate the beginning of draft round.
After visualizing these trends, we can gain value in the draft by selecting players at a position when the relative value of that position is its highest. We can break down the draft into which picks are best in each round.
Round 1: Quarterbacks
Fans of every team dream of finding a Tom Brady or Tony Romo at the end of the draft (or even after it), have them blossom into a superstar and win the big game. Unfortunately, it’s a lot less likely than we would like it to be. For every diamond in the rough, there are a whole lot of very dull rocks.
The quarterback graph shows QBs have a very high relative value early in the draft, but it quickly decays; drafting a quarterback after the second round is typically a negative value decision (comparing to the average draft pick AV for all positions). Part of the reason this is true is that only 32 players can start at QB at a time, while there is more need for rotational players at other positions. Players that never get to play have zero AV per season, and so many late round QBs ultimately provide no value to that team that drafted them.
Quarterbacks seem to bust at a higher rate than other positions taken early in the draft, but this risk is offset by the immense value good QB play adds to an NFL offense. Drafting quarterbacks in the first round brings the highest of highs or the lowest of lows, but as cruel as some teams seem to have it, the balance is favorable. Teams needing improvement at the QB position should stop dreaming and draft an early round prospect, while remaining cautious of dry QB classes.
Round 2: Linebackers & Running Backs
Despite the increasing amount of running back by committee (RBBC) in the NFL today, running backs taken early in the draft actually add a lot of value to NFL teams. First round RB Todd Gurley was Rookie of the Year in 2015. Running backs taken after the fourth round tend to add about the same value as other position.
Linebackers provide good relative value no matter the round drafted, but the advantage is largest in round two. The pattern for linebackers is very similar to the pattern for running backs, except their value holds up better late in the draft.
Rounds 3-4: Offensive Linemen
Offensive linemen add more value on average when drafted than any other position. This advantage peaks in rounds three and four, drafting an offensive linemen in the third round gives you about the same value as adding a player of a different position one round earlier. On average a linemen drafted 80th overall will add the same value to an NFL team as a player of a different position drafted 50th. Good offensive line play is incredibly important to NFL success, which is why teams are lucky offensive linemen succeed at a higher rate than other positions.
Rounds 5-6: Defensive Linemen & Defensive Ends
Defensive line talent in the NFL Draft has a lower peak than most positions, but it decays at a slower rate, and in the 5th & 6th rounds defensive linemen provide very strong relative value. Teams looking to shore up defensive line or defensive end depth should focus on other needs first and enjoy the depth at the position. The depth does eventually empty, however, as drafting a defensive lineman in the seventh round is actually a low-value proposition.
Round 7: Punters & The Defensive Backs Lottery
Defensive Backs begin as a low relative value pick but the position plateaus after the fourth round, which makes them very appealing as the draft winds to a close. Defensive Backs drafted at the tail end of the seventh round offer almost identical value on average to DBs drafted two full rounds earlier. Similar to WRs, starting corners should be drafted earlier, but filling depth at the corner and safety can be done on day three. Finally, punters provide the same average value no matter when drafted so later is better.
What about Wide Receivers?
The data shows Wide Receivers are a below average acquisition throughout the draft, despite the recent Wide Receiver revolution of Brown, Hopkins, Beckham Jr. among others. According to the data the best time to gamble on wide receivers is at the start of the third round, where WR relative value is about equal to other positions. This is particularly surprising given how pass-oriented most NFL offenses are today.