Have Super Bowl winners been built through the draft or free agency?

On the most recent episode of the Steelers Stat Geek podcast, I was asked the question about the roster make up of players drafted by the Super Bowl champions versus those acquired through free agency. Looking at the Super Bowl winners over the last 10 years, I was able to compile some interesting data looking at if teams are now building more through free agency versus the NFL draft.

First, I must explain the parameters of the data I was able to compile. In order to properly filter players’ draft status on Pro Football Reference, I looked at players who started at least half of the regular season games (8, including 2021) for each team the year they won the Super Bowl. By using this number, teams did not necessarily end up with 22 starters as what would be expected.

Additionally, I classified all the starters as being in one of three categories: Drafted, free agent, or undrafted. I left undrafted players as its own category because getting the exact data as to which team a player landed after not being selected in the NFL draft can be tricky. Sometimes players are picked up by a team and released even before they make it to training camp. Would that player be considered part of their original team or acquired via free agency? Since it was a bit of a gray area, I simply left it as its own category. If you wish, you could almost look at that percentage as the “margin of error” as players could fall into either of the other two categories if they were the only options.

One other item of note before looking at the numbers, if a player was drafted by a team and left via free agency but returned at another time, they will show up as a drafted player. Each starting player was simply classified by being drafted by the team with which they won the Super Bowl or drafted by a different team.

Rather than get into any of the breakdown beforehand, let’s simply see how the numbers fell. Each category was also given as a percentage to show how much of the starting lineup was represented. Also, the total averages over the final 10 years will be given at the end.

2021 Los Angeles Rams:

21 starters
11 drafted (52.4%)
8 free agents (38.1%)
2 undrafted (9.5%)

2020 Tampa Bay Buccaneers:

21 starters
14 drafted (66.7%)
6 free agents (28.5%)
1 undrafted (4.8%)

2019 Kansas City Chiefs:

23 starters
10 drafted (43.5%)
11 free agents (47.8%)
2 undrafted (8.7%)

2018 New England Patriots:

22 starters
13 drafted (59.1%)
7 free agents (31.8%)
2 undrafted (9.1%)

2017 Philadelphia Eagles:

22 starters
12 drafted (54.5%)
8 free agents (36.4%)
2 undrafted (9.1%)

2016 New England Patriots:

20 starters
12 drafted (60.0%)
4 free agents (20.0%)
4 undrafted (20.0%)

2015 Denver Broncos:

21 starters
10 drafted (47.6%)
9 free agents (42.9%)
2 undrafted (9.5%)

2014 New England Patriots:

20 starters
12 drafted (60.0%)
5 free agents (25.0%)
3 undrafted (15.0%)

2013 Seattle Seahawks:

24 starters
16 drafted (66.7%)
4 free agents (16.7%)
4 undrafted (16.7%)

2012 Baltimore Ravens:

20 starters
11 drafted (55.0%)
5 free agents (25.0%)
4 undrafted (20.0%)

Averages:

21.4 starters
12.1 drafted (56.5%)
6.7 free agents (31.3%)
2.6 undrafted (12.1%)

The first thing that jumped out at me was that, despite the narrative of being a team that was built through free agency, the Rams had a higher percentage of starters this season whom they drafted. The only team in the last 10 years to win the Super Bowl with more free agents then drafted players what is the Kansas City Chiefs in 2019. I was surprised their percentages were higher than the Los Angeles Rams.

It should be noted that no team crossed the 50% threshold when it came to their starters being acquired in free agency, including the Chiefs. They were only two teams who did not have at least half of their starters during their Super Bowl season as players they drafted with the 2015 Denver Broncos joining Kansas City.

Even in the era of NFL free agency frenzy, the last 10 Super Bowls have seen less than one-third of the starters for those teams during the season come to the franchise after being drafted by another team. While the 2021 Los Angeles Rams were above the average over the last 10 years, it wasn’t by much.

For a second comparison, let’s look at the same breakdown for the 2021 Pittsburgh Steelers.

2021 Pittsburgh Steelers:

21 starters
16 drafted (76.2%)
5 free agents (23.8%)
0 undrafted (0%)

What’s likely not surprising for Steelers’ fans is that more than three-quarters of the team has been built through being drafted by Pittsburgh. To me, the most surprising thing was the Steelers did not have a single player start eight games in 2021 who was undrafted. Going back just a season or two, the Steelers would have had quite a high percentage with players such as Alejandro Villanueva, Matt Feiler, Mike Hilton, Ramon Foster, and other undrafted gems the Steelers had developed. But following the 2020 season, none of those players were left in a starting position.

One last thing to finish off this exercise, let’s look at how the 2022 Pittsburgh Steelers roster is shaping up. Obviously we have no idea which players will start at least eight games this coming season, but based on the estimated starting positions I averaged out what the breakdown could be. With more than one uncertainty, I ended up landing at numbers which would fall in the middle based on the Steelers current roster.

Estimated 2022 Pittsburgh Steelers:

22 starters
14 drafted (63.6%)
7 free agents (31.8%)
1 undrafted (4.5%)

Estimated breakdown:
Drafted: 3 or 4 OL, 1 RB, 2 WR, 1 TE, 2 DT, 2 OLB, 1 ILB, 1 CB, 1 or 2 S
Free Agents: 1 or 2 OL, 1 QB, 1 WR, 1 DT, 1 ILB, 1 or 2 S
Undrafted: 1 CB

Right away, it appears that the Steelers would have just above the average of the last 10 Super Bowls when it comes to the percentage of their starters being acquired through free agency. This number also does not count cornerback Levi Wallace as he technically falls in the undrafted category.

Of course, the 2022 NFL draft has yet to occur and there is the possibility that multiple players selected could find their way into starting more than half the games by the end of the season. Since we don’t know who these players are at this time, this could inflate the number when it comes to drafted players starting half the games.

One last item of note, there is not a league average to compare these numbers to in order to know if it’s really different for Super Bowl winners versus all the other NFL teams. As long as it took to compile the data for one team each of the last 10 years, I would be lucky to be able to calculate all 32 teams over the last decade before the kickoff of the 2022 NFL season.

If nothing else, it was interesting to look at the numbers and see that it was the 2019 Kansas City Chiefs which built their roster more through free agency than the 2021 Los Angeles Rams.

The entire Steelers Stat Geek podcast can be heard below: