On Tuesday, we did the same for defense.

Today, let’s look at the average age of each team overall in 2017. For reference, here are last year’s results. You won’t be surprised to see Cleveland grade out as the youngest team in 2017 by over a full year. The Browns also failed to win a game, so youth didn’t work out for that team.

But the second-youngest team in football was the Jacksonville Jaguars, who nearly won the AFC. The Jaguars held a lead in the AFC Championship Game, before losing to the third-oldest team in the NFL… the Patriots.

The table below shows the average age of each team last season.

Why were the Jaguars so young? Let’s take a look at the full Jacksonville roster, sorted by AV:

Yes, the team’s best player (Campbell) was one of its oldest. But Jacksonville also got 8+ points of AV from players who were under 23 years old at the start of last season, in Robinson, Jack, Ngakoue, Fournette, and Ramsey. Not coincidentally, those were 5 of the team’s first three picks in the 2016 and 2017 drafts, and hitting on those players makes a huge difference! The 6th was 2017 third round pick Dawuane Smoot, who was just a role player as a rookie.

And the Jaguars have a pretty young passing game: the team’s quarterback and top five wide receivers all were 25 or younger at the start of the 2017 season.  Combined with a young offensive line and a very young running back, and Jacksonville has a really young offense in place for years to come.  The addition of Donte Moncrief this offseason won’t change that; he just turned 25 in August.

Jacksonville had six Pro Bowlers on defense, and only one was older than 27 years old in 2017.  And that doesn’t include Dante Fowler, who was 23 years old last year but recorded 8 sacks.  In other words, don’t expect the Jaguars to be a one-year wonder.

Being young isn’t by itself a virtue: the Browns ranked in the bottom 5 in points allowed, yards allowed, net yards per attempt allowed, net yards per rush allowed, turnovers forced, and first downs allowed. But Cleveland was, by far, the youngest defense in the NFL last season.

In 2016, the Browns defense had an average AV-adjusted age of just 25.2; the Falcons were the second-youngest defense at 25.8. In 2017, the Falcons again had an average AV-adjusted defense that was just 25.8 years old. But the Browns? That number dropped to just 24.5! The Browns defense was even younger than the Browns offense, and was by far the youngest unit in all of football:

We can look at the Browns defense in more depth, just as we did with the team’s offense yesterday: other than McCourty, nobody was even 28 years old on the defense.

In 2018, Collins will be the oldest player on defense, and he turns 29 in October. The Browns selected Myles Garrett and Jabrill Peppers in the first round last year, and both will still be 22 when the season starts; this year, Cleveland took 21-year-old cornerback Denzel Ward with the 4th overall pick.  As a result, the Browns should once against have one of the youngest defenses in the NFL.

As for Carolina? The 2017 Panthers had five major contributors who were in their 30s: LB Thomas Davis (34.4 last year),  S Mike Adams (36.4), DE Mario Addison (30.0), DE Julius Peppers (37.6), and DE Charles Johnson (31.1).  All but Johnson are returning this year, and the 2018 Panthers defense will also rely on three other members of the secondary (in addition to Adams) who are in their 30s in Colin Jones and Captain Munnerlyn and Da’Norris Searcy.

Carolina only had three regular defensive players — James Bradberry, Shaq Thompson, and Daryl Worley — that you could reasonably label as young (under 26 at the start of the season). The Panthers selected cornerback Donte Jackson in the second round this year, but otherwise, that doesn’t look super likely to change much. Expect the Panthers defense to be very old in 2018, unless injuries hit so hard that the team is forced to rely on younger players.