The Patriots are the consensus pre-season favorites to win the Super Bowl next February. The going odds that they will take home the Lombardi Trophy are, astonishingly, almost even at 9 to 5. The optimism in New England is due to the acquisition of three star players—wide receivers Randy Moss and Dante Stallworth, and linebacker Adalius Thomas.
MOSS AND STALLWORTH
The wide receiver position was seen as one of the Patriots' weaknesses last year, so the off-season upgrades are expected to dramatically improve their passing game. Unspectacular players such as Reche Caldwell and Jabar Gaffney became Tom Brady’s primary targets by the end of last season. The combination of a quarterback as good as Brady and receivers as talented as Moss and Stallworth could make New England’s passing attack dominant. But just how good can we expect them to become?
By replacing the performance of Patriots’ top two receivers of ’06 with the appropriate stats of Moss and Stallworth, we can estimate the most important measure of a team’s passing game—passing yards per attempt.
First, some assumptions: Tight ends and running backs will have the same performance as last year. Tom Brady will have his usual brilliant season. He’ll throw as few interceptions per attempt as he did last year, and he’ll be highly accurate with a 61.9% completion rate, which happens to be both his career average and last year’s rate. (Brady has been remarkably consistent. His best year was 2001 with a 63.9% completion rate, and his worst was 2003 with a 60.2% rate.) We’ll also assume both new receivers will remain healthy all year.
First, let’s look at Randy Moss. His stats over his last two seasons at Oakland are listed below. ADJ YDS is receiving yards adjusted for playing a full 16 game season.
YR G REC YDS AVG REC/G ADJ YDSMoss’s performance in 2006 was obviously hurt by playing with a sub-par team. Raiders quarterback Andrew Walter cannot be compared to Brady. Moss’s performance in 2005 was actually better than his final year in Minnesota, when he wasn’t even the top receiver for the Vikings. We’ll use his ’05 stats.
2005 16 60 1005 16.8 3.8 1005.0
2006 13 42 553 13.2 3.2 682.3
Despite all the attention on Moss, Dante Stallworth may prove to be the better acquisition. His stats over the last two years are below. He was in Philadelphia in ’06, and New Orleans in ’05.
YR G REC YDS AVG REC/G ADJ YDSStallworth had impressive stats both years. After projecting his numbers for playing a full 16 game season in ’05, we’ll use the average of his stats for the last two years.
2005 12 38 725 19.1 3.2 967.7
2006 16 70 945 13.5 4.4 945.0
Last year, New England’s passing offense was mediocre. They ranked 11th in total yards, but more importantly, only 15th in passing efficiency with 6.81 yards per attempt. To see how much that stat can improve we’ll start by looking at the ’06 receiving corps. WRs with fewer than 3 catches are excluded to save space.
NAME G REC YDS AVG REC/G ADJ YDSNow let’s replace the Patriot’s top two receivers with Moss and Stallworth. We’ll assume the #3 receiver remains Troy Brown, or at least will have stats very similar to his. We’ll also leave the 4th and 5th receivers as they are. Those receptions may go to Caldwell, Gaffney or Jackson, or to second tier acquisions Wes Welker and Kelley Washington, depending on who is healthy and active. But the resulting yardage should be similar for the #3 receivers and below on the depth chart. Below is the Patriot’s projected receiving corps for ’07.
Reche Caldwell 16 61 760 12.5 3.8 762.5
Doug Gabriel 12 25 344 13.8 2.1 460.0
Troy Brown 16 43 384 8.9 2.7 382.7
Jabar Gaffney 10 11 142 12.9 1.1 227.0
Chad Jackson 12 13 152 11.7 1.1 202.8
NAME G REC YDS AVG REC/G ADJ YDSWhere last year the Pat’s WRs contributed 1798 yards, next year’s squad should produce about 2706 yards, a 50% improvement. Add a steady 170 catches for 1792 yards from TEs and RBs for a total of 362 receptions. To achieve that number of receptions given a 62% completion rate would require 584 attempts.
Randy Moss 16 61 1021 16.8 3.8 1021.0
Dante Stallworth 16 61 991 16.3 3.8 991.0
Troy Brown 16 43 384 8.9 2.7 382.7
(Jabar Gaffney) 10 11 142 12.9 1.1 227.0
(Chad Jackson) 12 13 152 11.7 1.1 202.8
The result is 362 catches for 4498 yards on 584 attempts, improving the Patriot’s pass efficiency from 6.81 to 7.70 yds/att. This would rank New England’s passing offense third in 2006 and 21st out of 160 in the last five seasons. But what does this mean in terms of wins?
By using a regression model to estimate regular season wins based on efficiency stats, we can compare how many wins the Patriot’s should expect given both last year’s and this year’s receivers.
The regression model uses each team’s offensive and defensive running and passing efficiency stats, plus turnover rates and penalty yards, to calculate a probability of the outcome of any given game. After calculating each game’s probability for the 2007 season, we can then sum the probability of each possible season outcome for the Patriots to estimate how many wins a team will have.
For the Patriots, we’ll run the process twice, first using the pass efficiency from ’06, and then with the projected ’07 pass efficiency. Here is how the ’07 season would look using the old stats:
Vis. Home P(V) P(H)Using the law of total probability, we can estimate the Patriots would win approximately 9 games this year, given their exceptionally difficult schedule. Here is the actual distribution:
NE NYJ 0.49 0.51
SD NE 0.57 0.43
BUF NE 0.24 0.76
NE CIN 0.47 0.53
CLE NE 0.12 0.88
NE DAL 0.41 0.59
NE MIA 0.50 0.50
WAS NE 0.19 0.81
NE IND 0.27 0.73
NE BUF 0.60 0.40
PHI NE 0.57 0.43
NE BAL 0.34 0.66
PIT NE 0.41 0.59
NYJ NE 0.32 0.68
MIA NE 0.32 0.68
NE NYG 0.56 0.44
But with their new receivers, New England can expect better probabilities. Here is their revised 2007 season and the associated total probabilities of season wins:
Vis. Home P(V) P(H)
NE NYJ 0.58 0.42
SD NE 0.48 0.52
BUF NE 0.18 0.82
NE CIN 0.56 0.44
CLE NE 0.09 0.91
NE DAL 0.49 0.51
NE MIA 0.59 0.41
WAS NE 0.14 0.86
NE IND 0.34 0.66
NE BUF 0.68 0.32
PHI NE 0.49 0.51
NE BAL 0.42 0.58
PIT NE 0.33 0.67
NYJ NE 0.25 0.75
MIA NE 0.25 0.75
NE NYG 0.64 0.36
The Patriots are now projected to win 10 games instead of 9. The addition of Moss and Stallworth are worth 1 additional win. I expected a much larger difference, particularly because offensive pass efficiency is the factor with the most weight in the regression model. But another way to look at the improvement is to compare how the game-by-game probabilities changed. Notice that the addition of Moss and Stallworth are worth about a 9 point improvement in the probability to win each game. That’s an 18 point swing when considering the opponent’s win probability is equally reduced.
Projecting the improvement to the Patriot’s defense due to Adulius Thomas’s addition is tougher than for the WRs because it is much harder to quantify Thomas’s contribution to team defense. He is extremely versatile and athletic enough to impact every part of defensive football, from sacks to stopping the run to defending passes.
I propose a simpler but less exact approach. We will compute the share of Thomas’s contribution to his former team’s defense. The Ravens’ defense was historically good in 2006, ranking first or second in nearly every statistical category. We will improve the Patriot’s defensive stats towards those of the Ravens in proportion to Thomas’s share of overall team defense. In other words, if Thomas counted for half the tackles, assists, and sacks of the Ravens, then we would credit the Patriots with an improvement of 50% of the difference between Baltimore and New England’s team stats.
In 2006, The Ravens’ and Thomas’s stats were:
TKL AST SCK INT PD FF FRThomas recorded 9% of the Ravens’ tackles and 18% of their sacks. Excluding the forced fumble stat, the average share of Thomas’s contribution was 9%. To be generous, and to account for moving to a team with fewer stars where he can make a bigger impact, we’ll give Thomas credit for 10%.
Ravens 707 200 60 28 111 12 11
Thomas 64 19 11 1 7 0 1
Thomas(%) 9% 10% 18% 4% 6% 0% 9%
The adjustment to New England’s defensive efficiency stats is calculated below. YPA is passing yards per attempt, YPR is yards per run, and INTPA is interceptions per pass attempt.
YPA YPR INTPAHere is how NE’s season looks with their new WRs and Adalius Thomas.
NE ’06 5.70 3.90 0.042
BAL ’06 5.29 3.30 0.055
Adjustment -0.04 -0.06 +0.002
NE ’07 5.66 3.84 0.044
Vis. Home P(V) P(H)
NE NYJ 0.59 0.41
SD NE 0.47 0.53
BUF NE 0.17 0.83
NE CIN 0.57 0.43
CLE NE 0.09 0.91
NE DAL 0.50 0.50
NE MIA 0.60 0.40
WAS NE 0.14 0.86
NE IND 0.35 0.65
NE BUF 0.69 0.31
PHI NE 0.47 0.53
NE BAL 0.43 0.57
PIT NE 0.31 0.69
NYJ NE 0.24 0.76
MIA NE 0.24 0.76
NE NYG 0.65 0.35
Thomas’s contribution is significantly less dramatic than that of Moss and Stallworth. He counts for about 1 additional point of probability per game, for a 2 point swing, and adds far less than one win to the Patriot’s projections.