The team that won the Cup had exceptional injury luck and suffered no blueline injuries to speak of, and was able to trot out this blueline every night in the playoffs:
Kempny-Carlson
Orlov-Niskanen
Djoos-Orpik
- Niskanen aged out. He was dreadful in 2018-19, rebounded nicely in 2019-20 with a fresh start and superior coaching in Philly, but I suppose the miles were already taking their toll and he's now already decided to retire from the league.
- Orpik was even older, and he fell off a cliff even faster than Niskanen. He returned for the one year in 2018-19, showed his age in a big way, and he retired last summer.
- Kempny has battled injury and struggled to find his game again when healthy. Then he suffered a freak Achilles injury this offseason that will see him miss the next 6-8 months. Rotten luck.
- Djoos fell completely off a cliff, for reasons that aren't entirely clear. He was so good as a rookie in the Cup year, but battled injury and lost his slot in 2018-19. He was relegated to the seventh defenseman for much of that year and saw a trade to Anaheim in early 2019-20. He has improved in Anaheim, lending more credence to the idea that the coaching falloff from Trotz to Reirden hurt the young D in Washington.
Breaking the corps down into thirds, Carlson and Orlov have remained in DC and are generally solid to very good on most nights.
Orpik and Niskanen were major contributors right up to the Cup year, but the miles were already piling up. Both are now retired from the league. Between the two of them, that's a ton of veteran institutional memory they've lost and haven't replaced.
With Kempny and Djoos, it's probably a few things. The coaching downgrade really had an effect here, I think. There is also a case to be made that they got everything they could ever want out of both players in the Cup run. One was a rookie playing a heady third-pairing role, while reclamation project Kempny was holding down a top-pairing role after he came over from Chicago. A certain amount of regression was always likely. The Caps really caught lightning in a bottle with both en route to a Cup win. Injuries to both since June 2018 exacerbated those downward trends.
The corps is in the process of integrating three good prospect defensemen (Siegenthaler, Fehervary, Alexxev), so there are growing pains to expect there, but you would want to be giving them plenty of veterans to serve as mentors and take the pressure off the younger D while they get their feet under them. Where someone like Savard or Brodie would have been ideal, they go out and sign... Schultz to replace Gudas, who himself replaced Orpik. It's hard to see that working out.
Stronger coaching across the board will help next season, but either they get a tremendous rookie campaign from Fehervary, a good sophomore season from Siegenthaler, and a resurgence from Jensen or they will have to consider a mid-season trade.