Well defensive rebounding was a big part of why they were the 2 worst defenders on the team. All of advanced stats point to them being the worst defenders on the team.
This is DRPM from ESPN. Hali is 90th out of 91 PGs. Fox is 29th.
http://www.espn.com/nba/statistics/rpm/_/page/3/sort/DRPM/position/1
This is RAPTOR rating from 538. Sort for Kings
https://projects.fivethirtyeight.com/nba-player-ratings/
This is LEBRON metric. Sort for Kings
https://www.bball-index.com/lebron-data-viz/
This is DRAPM
http://nbashotcharts.com/rapm?id=-1217804387
As far as defensive rebounding, use this one from NBA.com
https://go.nba.com/ynas
The most important columns are the DREB CHANCES, ADJUSTED DREB CHANCES %, and the AVG DREB DISTANCE.
The DREB CHANCES tells you how good a player creates potential rebounds. But those numbers have to be normalized by 36 minutes if you want to compare players to players and NBA does not let you do that there. I had to copy to excel to do it.
ADJUSTED DREB CHANCES % tells you how good a player contributes to team rebound in general.
AVG DREB DISTANCE tells you how far away from the basket a player rebounds. This can somewhat tells you what kind of defensive role a player has. Shortest distance are likely center and largest distance are likely guards. Forwards are in between.
Fox and Hali don't track rebounds well. I mean they just don't get closer to where a ball could land to even create a chance for it.
As far as the the signings of TT and Len, I can think of a few reasons:
- Holmes is pretty well below average rebounder for a center
- Can't really sign guards since Fox and Hali are needed for offense and will play big minutes