The not completely awful players
DE Quinton Jefferson - Signed for one season with the New York Jets
Seattle made a concerted effort to blow up their defensive line this past offseason. Gone were players such as Jefferson and in were Dre'Mont Jones, Jarran Reed, and Mario Edwards. Is Seattle's defensive line better in 2023? If not else, it's no worse. Seattle allows 4.4 yards per carry this year but gave up 4.9 in 2022.
Jefferson always had the capability of being a decent pass rusher, but he stunk at stopping the run. This has held true this year as he has 6 sacks but his run defense graded, as given by Pro Football Focus (subscription required) is only 37.0, sixth-worse in the league.
DT Shelby Harris - Signed for one season with the Cleveland Browns
Harris is on one of the better defensive lines in football - if not the best - and is a rotational player. Still, he does his job well. He is also graded as the 25th-best interior defender in 2023, per PFF. For a player who has several years in the league, finding a spot like the Browns was perfect as there was talent around him and he was not overtaxed with snaps.
Harris has solid grades across the board and has no glaring weaknesses. He also wasn't a bad player for the Seahawks last year. Maybe once he hits free agency again next offseason, Seattle should try to re-sign him.