Marcus Thompson gives in detail how badly the Warriors struggled on the glass:

The Warriors had a difficult time boxing out the Kings’ active big men, who looked a step quicker and a tad hungrier. Rookie center DeMarcus Cousins had 20 points and eight rebounds in 22 minutes. Forward Omri Casspi had nine rebounds off the bench.

The Kings’ 21 second-chance points helped them overcome the 21 turnovers that the Warriors forced.

If that wasn’t bad enough, Jeff Adrien, training camp invitee looking to fill out the 15th spot on the squad who I thought was going to be the Warriors version of Paul Milsap (defensively) only registered one rebound in 15 minutes of action.