Honestly, most of these injuries haven't had anything to do with a shortened off-season. That's been overblown, mainly driven by LBJ.
1. A lot of these injuries were just freak accidents. Guys landing awkwardly, stepping on players, running into each other, etc. Harden's soft tissue injuries are probably more so due to him being lazy as shit in the off-season and showing up overweight and out of shape.
2. That theory never held much water imo anyway. After the pandemic hit last year, these guys had 4 MONTHS before bubble ball began. Many teams weren't invited to the bubble, so they had the longest off-season of their careers. The teams that did get invited but didn't make the playoffs also had a shit ton of time off, as did the teams who got eliminated early. So many teams had 8-9 months off between the start of the pandemic and the start of this season, some teams only played competitive basketball for 1-2 months out of those 9 months, and a couple played competitive basketball for 3 of those 9 months.
I mean of significant injuries to star (or very key) players we've got...
Lakers - LeBron - (age), fatigue, most likely to have been affected by short offseason. AD - Injury prone, gets groin strain after injury plagued regular season. The Lakers might be the only team that could claim this sort of thing.
Nuggets - Jamal Murray - tears ACL while driving to the basket, no contact made. These injuries happen every single season. I'm not privy to if Murray had an injury plagued season like Derrick Rose did in 2012 or not, but if he didn't , I view it more freak than not.
Nets - James Harden - as you said, he's lazy, he purposely blew the Rockets off and likely stayed out of shape to force a trade. This basically cost him the season and has nothing to do with short offseason. Kyrie Irving had Giannis land on his ankle in what I view as an unfortunate accident. Kyrie is also injury prone.
Celtics - Jaylen Brown breaks his wrist, something that can't really be blamed on having a short offseason and condensed schedule
76ers - Embiid partially tears his meniscus in the 1st round, misses a few games, but comes back and plays on it, though at times definitely looked bother by it. He is also an injury prone player.
Jazz - Mike Conley battled hamstring issues, and Donovan Mitchell got his ankle stepped on. Hamstring you could blame on condensed scheduling, but not for Mitchell.
Suns - Chris Paul, an injury prone player, hurts shoulder in 1st round and is limited most of the series. However, he fully recovers and has an amazing second round before getting COVID and knocking him out the first two games of the WCF.
Clippers - Kawhi, an injury prone player, who sits just for the hell of it to rest, gets an ACL sprain in G4 of the 2nd round going up for a shot. He has yet to return, but another injury I wouldn't blame on anything other than bad luck.
Warriors - Klay Thompson tears his achilles after already missing an entire season prior to this season even starting. Has nothing to do with anything.
Bucks - Greek has a collision with a Hawks player resulting in his knee bending awkwardly. Again has nothing to do with short offseason/condensed schedule.
Hawks - Ref steps on Trae Youngs ankle, knocks him out at least one game.
As you said, some of these teams didn't even have a game from March until December. Others had time off from March until the bubble, and most got knocked out early in the bubble.
