In 2023 and 2024, the Detroit Lions had a top-five run defense in the NFL. 2024's No. 5 ranking was a little misleading, as they were in the bottom half of the league in yards per carry allowed and faced the fewest rushing attempts. But there's no apology necessary when it comes to rendering opposing offenses one-dimensional.
Last season, with the change from Aaron Glenn to Kelvin Sheppard as defensive coordinator, the Lions fell to 14th in rushing yards allowed while maintaining that standing in the bottom-half of the league yards per carry allowed. The difference can be chalked up in-part to facing 4.5 more rushing attempts per game, as could be expected when going from a 15-2 record one season to a 9-8 mark the next.
Despite evidence to the contrary, Sheppard at one point attempted to say the Lions were a stouter run defense than it seemed they were. But he was only calling the defense. He's not on the field executing (or failing to execute) what's called, or not performing up to par.
ESPN analyst practically confirms a Lions' free agent who will be gone
Ahead of the start of free agency, ESPN's Seth Walder offered up some underrated and overrated free agents based on underlying deeper metrics.
Rounding out the overrated group was Lions defensive tackle DJ Reader.
"Reader is a nose tackle whose run-stuffing numbers have not been impressive lately. Run stop win rate is not a fan of what he did last season, with a sixth-percentile score among interior defenders."
Walder did acknowledge some general "noise" in run-stopping metrics, while also noting defensive tackles like Reader tend to have cleaner numbers than other positions. And as he noted, Reader's struggles are backed by more basic stats as well.
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"Reader's tackle rate against the run was only in the ninth percentile. Even if we compare only his play at nose tackle to others' play at the position, that number is still just in the 23rd percentile. He was below average in NFL Next Gen Stats' run stop rate and stuff rate, relative to other defensive tackles, too."
On the analytics side, Pro Football Focus was kinder to Reader's work last season. He landed 30th among 134 qualifying defensive tackles in overall grade, with a top-40 run defense grade and a top-25 pass rush grade despite registering zero sacks.
Reader's primary value is as an interior run defender, and he has declined in that phase over his two seasons as a Lion. The general tea leaves have suggested he won't be back next season, and now we have more data to push it toward a practical lock.